Edgar Filing: Gevo, Inc.

424B5

Filed Pursuant to Rule 424(b)(5)
Registration File No. 333-187893

The information in this prospectus supplement is not complete and may be changed. This prospectus supplement and the accompanying prospectus are not an offer to sell these securities and are not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

Subject to completion, dated December 10, 2013

PRELIMINARY PROSPECTUS SUPPLEMENT

To Prospectus dated May 15, 2013

GEVO, INC.

Common Stock Units

Consisting of One Share of Common Stock and a Warrant to Purchase of a Share of Common Stock

$ per Common Stock Unit

• We are offering common stock units, with each common stock unit consisting of one share of our common stock and a warrant to purchase of a share of our common stock (and the common stock issuable from time to time upon exercise of each of the warrants) pursuant to this prospectus supplement and the accompanying prospectus. Each common stock unit will be sold to investors in this offering at a negotiated price of $ per common stock unit. The common stock units will not be issued or certificated. The shares of common stock and the warrants are immediately separable and will be issued separately, but will be purchased together in this offering.

• The warrants will be exercisable during the period commencing from the date of original issuance and

ending on December , 2018, the expiration date of the warrants, at an initial exercise price of $ per share of common stock. See “Description of Our Common Stock” and “Description of Our Warrants” for more information on the securities offered hereby.

• Our common stock is traded on the NASDAQ Global Market under the symbol “GEVO.” On December 9, 2013, the last reported sale price of our common stock on the NASDAQ Global Market was $1.70 per share. The warrants are not and will not be listed for trading on the NASDAQ Global Market, or any other securities exchange.

Investing in our securities involves a high degree of risk. Before buying any securities, you should review carefully the risks and uncertainties described under the heading “Risk Factors” beginning on page S-14 of this prospectus supplement, on page 5 of the accompanying prospectus and in the documents incorporated by reference into this prospectus supplement.



	Per Unit	Total
Public Offering Price	$	$
Underwriting Discount⁽¹⁾	$	$
Proceeds, before expenses, to Gevo, Inc.	$	$

⁽¹⁾We have also agreed to reimburse the underwriter for certain out-of-pocket-expenses incurred by it. See “Underwriting” for more information on expense reimbursement.

Certain of our directors, officers and existing stockholders, including Total Energy Ventures International, Khosla Ventures I, L.P., Virgin Green Fund I, L.P. and Malaysian Life Sciences Capital Fund Ltd., or their respective affiliates, may participate in this offering and/or the concurrent offering of senior note units. Such directors, officers and existing stockholders have expressed an interest in investing up to an aggregate of approximately $7.3 million in this offering and/or the concurrent offering of senior note units. However, because expressions of interest are not binding agreements or commitments to purchase, the underwriter may determine to sell more, less or no securities in this offering and/or the concurrent offering of senior note units to any of these directors, officers and existing stockholders, or any of these directors, officers and existing stockholders may determine to purchase more, less or no securities in this offering and/or the concurrent offering of senior note units.

Concurrently with this offering of common stock units, we are offering senior note units, with each senior note unit consisting of $1,000 principal amount of convertible senior notes due December , 2023 (the “2013 Notes”) and warrants to purchase shares of our common stock (or a total of $ aggregate principal amount of 2013 Notes and warrants to purchase up to shares of our common stock if the underwriter for the concurrent offering of senior note units exercises in full its option to purchase such additional securities) (and the common stock issuable from time to time upon exercise of each of the warrants) pursuant to a separate prospectus supplement. This offering of common stock units is not contingent upon the concurrent offering of senior note units, and the concurrent offering of senior note units is not contingent upon this offering of common stock units. The warrants offered in the concurrent offering of senior note units are expected to have a materially higher exercise price compared to the warrants offered hereby, but are otherwise expected to be substantially similar.

We have granted the underwriter a 30-day option to purchase up to additional shares of common stock and/or warrants to purchase up to shares of common stock at a price per share of $ and at a price per warrant of $ , to cover over-allotments, if any.

Delivery of the shares of common stock and warrants is expected to be made on or about December , 2013.

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Piper Jaffray

The date of this prospectus supplement is December , 2013

TABLE OF CONTENTS


	Page
PROSPECTUS SUPPLEMENT

ABOUT THIS PROSPECTUS SUPPLEMENT		S-ii

CONVENTIONS THAT APPLY TO THIS PROSPECTUS SUPPLEMENT		S-iii

PROSPECTUS SUPPLEMENT SUMMARY		S-1

RISK FACTORS		S-14

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS		S-57

USE OF PROCEEDS		S-59

CAPITALIZATION		S-60

DILUTION		S-62

DESCRIPTION OF OUR COMMON STOCK		S-64

DESCRIPTION OF OUR WARRANTS		S-64

MATERIAL UNITED STATES FEDERAL INCOME TAX CONSEQUENCES		S-67

UNDERWRITING		S-74

NOTICE TO INVESTORS		S-78

LEGAL MATTERS		S-81

EXPERTS		S-81

WHERE YOU CAN FIND ADDITIONAL INFORMATION		S-81

INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE		S-81

PROSPECTUS

About This Prospectus		1

Conventions That Apply to This Prospectus		2

Gevo, Inc.		3

Risk Factors		5

Cautionary Statement Regarding Forward-Looking Statements		6

The Securities We May Offer		8

Ratio of Earnings to Fixed Charges		11

Use of Proceeds		12

Description of Capital Stock		13

Description of Debt Securities		16

Description of Warrants		23

Description of Units		25

Legal Ownership of Securities		27

Plan of Distribution		30

Legal Matters		32

Experts		32

Material Changes		32

Where You Can Find Additional Information		33

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ABOUT THIS PROSPECTUS SUPPLEMENT

This prospectus supplement and the accompanying prospectus are part of a registration statement that we filed with the U.S. Securities and Exchange Commission (the “SEC”) utilizing a “shelf” registration process. This document is in two parts. The first part is this prospectus supplement, including the documents incorporated by reference herein, which describes the specific terms of this offering. The second part, the accompanying prospectus, including the documents incorporated by reference therein, provides more general information. Generally, when we refer to the prospectus, we are referring to both parts of this document combined. We urge you to carefully read this prospectus supplement and the accompanying prospectus, and the documents incorporated by reference herein and therein, before buying any of the securities being offered under this prospectus supplement. This prospectus supplement may add or update information contained in the accompanying prospectus and the documents incorporated by reference therein. To the extent that any statement we make in this prospectus supplement is inconsistent with statements made in the accompanying prospectus or any documents incorporated by reference therein that were filed before the date of this prospectus supplement, the statements made in this prospectus supplement will be deemed to modify or supersede those made in the accompanying prospectus and such documents incorporated by reference therein.

You should rely only on the information contained in this prospectus supplement and the accompanying prospectus or incorporated by reference herein or therein. We have not authorized anyone to provide you with different information. No dealer, salesperson or other person is authorized to give any information or to represent anything not contained in this prospectus supplement and the accompanying prospectus. You should not rely on any unauthorized information or representation. This prospectus supplement is an offer to sell only the securities offered hereby, and only under circumstances and in jurisdictions where it is lawful to do so. You should assume that the information in this prospectus supplement and the accompanying prospectus is accurate only as of the date on the front of the applicable document and that any information we have incorporated by reference is accurate only as of the date of the document incorporated by reference, regardless of the date of delivery of this prospectus supplement or the accompanying prospectus, or the date of any sale of a security.

Unless otherwise mentioned or unless the context requires otherwise, all references in this prospectus to “the Company,” “we,” “us,” “our,” and “Gevo” refer to Gevo, Inc., a Delaware corporation, and its consolidated subsidiaries.

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CONVENTIONS THAT APPLY TO THIS PROSPECTUS SUPPLEMENT

This prospectus supplement and the accompanying prospectus contain estimates and other information concerning our target markets that are based on industry publications, surveys and forecasts, including those generated by the U.S. Energy Information Association (the “EIA”), the International Energy Agency (the “IEA”), and Nexant, Inc. (“Nexant”). Certain target market sizes presented in this prospectus supplement have been calculated by us (as further described below) based on such information. This information involves a number of assumptions and limitations and you are cautioned not to give undue weight to this information. Please read the section of this prospectus supplement entitled “Cautionary Note Regarding Forward-Looking Statements.” The industry in which we operate is subject to a high degree of uncertainty and risk due to a variety of factors, including those described in the section entitled “Risk Factors” beginning on page S-14. These and other factors could cause actual results to differ materially from those expressed in these publications, surveys and forecasts.

With respect to calculation of product market volumes:

•

product market volumes are provided solely to show the magnitude of the potential markets for isobutanol and the products derived from it. They are not intended to be projections of our actual isobutanol production or sales;

•

product market volume calculations for fuels markets are based on data available for the year 2011 from the IEA;

•

product market volume calculations for chemicals markets are based on data available for the year 2012 (the most current data available from Nexant); and

•

volume data with respect to target market sizes is derived from data included in various industry publications, surveys and forecasts generated by the EIA, the IEA and Nexant.

We have converted these market sizes into volumes of isobutanol as follows:

•

we calculated the size of the market for isobutanol as a gasoline blendstock and oxygenate by multiplying the world gasoline market volume by an estimated 12.5% by volume isobutanol blend ratio;

•

we calculated the size of the specialty chemicals markets by substituting volumes of isobutanol equivalent to the volume of products currently used to serve these markets;

•

we calculated the size of the petrochemicals and hydrocarbon fuels markets by calculating the amount of isobutanol that, if converted into the target products at theoretical yield, would be needed to fully serve these markets (in substitution for the volume of products currently used to serve these markets); and

•

for consistency in measurement, where necessary we converted all market sizes into gallons.

Conversion into gallons for the fuels markets is based upon fuel densities identified by Air BP Ltd. and the American Petroleum Institute.

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PROSPECTUS SUPPLEMENT SUMMARY

This summary is not complete and does not contain all of the information that you should consider before investing in the securities offered by this prospectus. You should read this summary together with the entire prospectus supplement and the accompanying prospectus, including our financial statements, the notes to those financial statements and the other documents that are incorporated by reference in this prospectus supplement and the accompanying prospectus, before making an investment decision. See the “Risk Factors” section of this prospectus supplement beginning on page S-14 for a discussion of the risks involved in investing in our securities.

Gevo, Inc.

Our Business

We are a renewable chemicals and next generation biofuels company. Our strategy is to commercialize biobased alternatives to petroleum-based products using a combination of synthetic biology, metabolic and chemical engineering and chemistry. In order to implement this strategy, we are utilizing a building block approach. We intend to produce and sell isobutanol from renewable feedstocks. Isobutanol is a four-carbon alcohol that can be sold directly for use as a specialty chemical in the production of solvents, paints and coatings or as a value-added gasoline blendstock. Isobutanol can also be converted into butenes using dehydration chemistry deployed in the refining and petrochemicals industries today. The convertibility of isobutanol into butenes is important because butenes are primary hydrocarbon building blocks used in the production of hydrocarbon fuels, lubricants, polyester, rubber, plastics, fibers and other polymers. We believe that the products derived from isobutanol have potential applications in substantially all of the global hydrocarbon fuels market, representing a potential market for isobutanol of approximately 1,000 billion gallons per year (“BGPY”), and in approximately 40% of the global petrochemicals market, representing a potential market for isobutanol of approximately 70 BGPY. When combined with a potential specialty chemical market for isobutanol of approximately 1.2 BGPY, we believe that the potential global market for isobutanol is greater than 1,100 BGPY.

We believe that products derived from our isobutanol will be drop-in products, which means that our customers will be able to replace petroleum-based intermediate products with renewable isobutanol-based intermediate products without modification to their equipment or production processes. The final products produced from our renewable isobutanol-based intermediate products should be chemically and physically identical to those produced from petroleum-based intermediate products, except that they will contain carbon from renewable sources. Customer interest in our renewable isobutanol is primarily driven by our production route, which we believe will be cost-efficient, and our renewable isobutanol’s potential to serve as a cost-effective, environmentally sensitive alternative to the petroleum-based intermediate products that they currently use. We believe that at every step of the value chain, renewable products that are chemically identical to the incumbent petrochemical products will have lower market adoption hurdles in contrast with other bioindustrial products because the infrastructure and applications for such products already exist. In addition, we believe that products made from biobased isobutanol will be subject to less raw material cost volatility than the petroleum-based products in use today because of the lower historical cost volatility of agricultural feedstocks compared to oil.

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during the fermentation process. We developed our technology platform to be compatible with the existing approximately 23 BGPY of global operating ethanol production capacity, as estimated by the Renewable Fuels Association (“RFA”). Our GIFT^® design can be used to retrofit existing ethanol capacity to produce isobutanol or to add renewable isobutanol production capabilities to an ethanol facility’s existing ethanol production by adding isobutanol fermentation capacity side-by-side with the facility’s existing ethanol fermentation capacity (collectively referred to as “Retrofit”). GIFT^® is designed to allow relatively low capital expenditure Retrofits of existing ethanol facilities, enabling a rapid route to isobutanol production from the fermentation of renewable feedstocks. We believe that our production route will be cost-efficient and will enable rapid deployment of our technology platform and allow our isobutanol and the products produced from it to be economically competitive with many of the petroleum-based products used in the chemicals and fuels markets today.

We expect that the combination of our efficient proprietary technology, our marketing focus on providing drop-in substitutes for incumbent petrochemical products and our relatively low capital investment Retrofits will mitigate many of the historical issues associated with the commercialization of renewable chemicals and fuels.

Direct Use Markets

Without modification, isobutanol has applications in the specialty chemical and gasoline blendstock markets. Since our potential customers in these markets would not be required to develop any additional infrastructure to use our isobutanol, we believe that selling into these markets will result in a relatively low risk profile and produce attractive margins.

Specialty Chemicals

•

Isobutanol has direct applications as a specialty chemical. High-purity and chemical-grade isobutanol can be used as a solvent and chemical intermediate. We plan to produce high-purity and chemical-grade isobutanol that can be used in the existing butanol markets as a cost-effective, environmentally sensitive alternative to petroleum-based products.

•

We believe that our production route will be cost-efficient and will allow for significant expansion of the historical isobutanol markets within existing butanol markets through displacing n-butanol, a related compound to isobutanol that is currently sold into butanol markets.

•

We estimate the total addressable worldwide market for isobutanol as a specialty chemical to be approximately 1.2 BGPY, or approximately $7.0 billion annually, based on average 2012 ICIS isobutanol pricing.

Gasoline Blendstocks

•

Isobutanol has direct applications as a gasoline blendstock. Fuel-grade isobutanol may be used as a high energy content, low Reid Vapor Pressure, gasoline blendstock and oxygenate. Based on isobutanol’s low water solubility, in contrast with ethanol, we believe that isobutanol will be compatible with existing refinery infrastructure, allowing for blending at the refinery rather than blending at the terminal.

•

Further, based on isobutanol’s high energy content and low water solubility, as well as testing completed by the National Marine Manufacturers Association, the Outdoor Power Equipment Institute and Briggs & Stratton, we believe that isobutanol has direct applications as a blendstock in high value specialty fuels markets serving marine, off-road vehicles, small engine and sports vehicle markets.

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•

We estimate the total addressable worldwide market for isobutanol as a gasoline blendstock to be approximately 40 BGPY, or approximately $100.0 billion annually.

Butene and Hydrocarbon Markets

Beyond direct use as a specialty chemical and gasoline blendstock, isobutanol can be dehydrated to produce butenes which can then be converted into other products such as para-xylene, jet fuel and many other hydrocarbon fuels and specialty blendstocks, offering substantial potential for additional demand. The conversion of isobutanol into butenes is a fundamentally important process that enables isobutanol to be used as a building block chemical in multiple markets.

Jet Fuel

•

We have demonstrated the conversion of our isobutanol into a renewable jet fuel blendstock that meets current ASTM International (“ASTM”) and U.S. military synthetic jet fuel blendstock performance and purity requirements. We have successfully delivered to the U.S. Air Force (“USAF”), the U.S. Army and the U.S. Navy a combined total of approximately 36,000 gallons of jet fuel made from isobutanol. We are working to obtain an ASTM standard specification for the use of such jet fuel blendstock in commercial aviation. We have already presented positive test results from fit-for-purpose testing of our biojet fuel to ASTM’s ‘alcohol-to-jet’ (“ATJ”) task force. The full ASTM specification for our ATJ fuel is expected to be issued in 2014.

•

Military and commercial airlines are currently looking to form strategic alliances with biofuels companies to meet their renewable fuel needs.

•

We estimate the global market for jet fuel to be approximately 80 BGPY, or approximately $210.0 billion annually.

Para-xylene (“PX”) and Polyethylene Terephthalate (“PET”)

•

Isobutanol can be used to produce PX, polyester and their derivatives, which are used in the beverage, food packaging, textile and fibers markets. PX is a key raw material in PET production.

•

We estimate the global market for PET to be approximately 50 million metric tons per year , or approximately $100.0 billion annually, of which approximately 30% will be used for plastic bottles and containers.

Butenes

•

Traditionally butenes have been produced as co-products from the process of cracking naptha in the production of ethylene. Historically, lower natural gas prices and reported reductions in the use of naptha as the feedstock for the production of ethylene have changed the projected type of co-products, resulting in a projected reduction in the volume of available butenes. This structural shift in feedstocks increases the potential market opportunity for our isobutanol in the production of butenes.

•

Chemical-grade isobutanol can be sold to isobutylene and n-butene (butenes) chemicals users for conversion into lubricants, methyl methacrylate and rubber applications.

•

We estimate the total addressable worldwide market for butenes to be approximately 2.1 BGPY, or approximately $6.7 billion annually.

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Other Hydrocarbon Fuels

•

Diesel fuel, gasoline, isooctane, isooctene and bunker fuel may also be produced from our isobutanol. We have demonstrated the conversion of isobutanol to isooctane and renewable gasoline. We have also converted isobutanol to kerosene with properties that we expect may be fit for diesel blending applications.

Competitive Strengths

Our competitive strengths include:

•

Renewable platform molecule to serve multiple large drop-in markets. We believe that our isobutanol will readily substitute for petroleum-based isobutanol and a portion of the petroleum-based n-butanol in use in the specialty chemicals market which exists today. We believe isobutanol can be readily blended with gasoline in existing infrastructure to serve the need for biofuels blending demanded by the U.S. Environmental Protection Agency (the “EPA”) for fuel manufacturers. We also believe that the butenes produced from our isobutanol will have potential applications in substantially all of the global hydrocarbon fuels market and will serve as renewable alternatives in the production of polyester, rubber, plastics, fibers and other polymers, which comprise approximately 40% of the global petrochemicals market. This broad potential as a platform molecule may enable our customers to reduce intermediate product cost volatility, diversify suppliers and improve feedstock security. We believe that we will face reduced market adoption barriers in contrast to other new bioindustrial products because products derived from our renewable isobutanol are chemically identical to petroleum-derived products, except that they will contain carbon from renewable sources.

•

Proprietary, low cost technology with global applications. We believe that GIFT^® is a proprietary, patent protected biological process capable of producing isobutanol cost-effectively from renewable carbohydrate sources, which we expect will enable the economic production of hydrocarbon derivatives of isobutanol. Our biocatalysts have demonstrated a product yield on sugar of approximately 94% of theoretical maximum by weight, which is close to the maximum actual yield attainable from fermentable sugars. Collectively, we believe that these attributes, coupled with our ability to leverage the existing ethanol production infrastructure, will create relatively low capital cost routes to renewable isobutanol production which will enable our isobutanol to be economically competitive with many of the petroleum-derived products used in the chemicals and fuels markets today. Additionally, GIFT^® is designed to enable the economic production of isobutanol and other alcohols from multiple renewable feedstocks, which will allow our technology to be deployed worldwide.

•

Capital-light commercial deployment strategy optimized for existing infrastructure. We have designed GIFT^® to enable capital-efficient Retrofits of existing ethanol facilities, which allows us to leverage the existing approximately 23 BGPY of global operating ethanol production capacity. Our Retrofit strategy supports a relatively low capital cost route to isobutanol production. Using a factored estimate based on the detailed design of our plant located in Luverne, Minnesota (the “Agri-Energy Facility”) in combination with our learning from the retrofit of that facility, we estimate base retrofit costs to convert an existing grain ethanol plant’s production capacity to isobutanol production capacity will be approximately $1.00 per gallon of existing annual ethanol capacity. This projection translates to approximately $50.0 million for a 50 million gallon per year (“MGPY’) ethanol facility and approximately $100.0 million for a 100 MGPY ethanol facility. These projected retrofit

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capital expenditures are less than estimates for new plant construction for the production of advanced biofuels, including cellulosic ethanol. We have also designed the implementation of our production technology to minimize the disruption of ethanol production during the Retrofit process, mitigating the costs associated with downtime as the plant is modified. Following the transition to isobutanol production, we expect the original plant to operate in essentially the same manner as it did prior to the Retrofit, producing a primary product (isobutanol) and a co-product (isobutanol distiller’s grains (“iDGs™”)). We have also commenced a licensing strategy whereby a licensee would invest the capital for the Retrofit of its ethanol plant. In return, Gevo, as the licensor, would expect to receive an up-front license fee and ongoing royalty payments from the project. In October 2013, Gevo signed a letter of intent with IGPC Ethanol Inc. to Retrofit their 40 MGPY ethanol plant.

•

GIFT^® demonstrated at commercially relevant scale. We previously completed the retrofit of a one MGPY ethanol facility in St. Joseph, Missouri with our proprietary engineering package designed in partnership with ICM, Inc. (“ICM”) and we successfully produced isobutanol at this facility. In May 2012, we commenced initial startup operations for the production of isobutanol at the Agri-Energy Facility and produced approximately 100,000 gallons of bio-based isobutanol for initial sale and future customer testing. In September 2012, as a result of a lower than planned production rate of isobutanol we made the strategic decision to pause isobutanol production at the Agri-Energy Facility at the conclusion of startup operations to focus on optimizing specific parts of the process to further enhance isobutanol production rates. In 2013, we successfully modified our Agri-Energy Facility which we believe will allow us to increase the production rate. In June 2013, we resumed the limited production of isobutanol operating one fermenter and one GIFT^® separation system in single production train mode at the Agri-Energy Facility. In August 2013, we expanded production at the Agri-Energy Facility to dual production train mode by adding a second fermenter and second GIFT^® system. For these initial production runs, we demonstrated fermentation operations at commercial scale combined with the use of our GIFT^® separation system using a dextrose (sugar) feedstock. Based on the results of these initial production runs, in October 2013 we commissioned the Agri-Energy Facility on corn mash for fully integrated production. We plan to continue producing isobutanol throughout the remainder of 2013 with the objective of testing production run rates and then further ramping up production toward nameplate capacity in 2014.

•

Off-take agreements and strategic relationships with chemicals, fuels, animal feed and engineering industry leaders in place. We have entered into off-take agreements and strategic relationships with global industry leaders to accelerate the execution of our commercial deployment strategy both in the U.S. and internationally. These agreements demonstrate demand for our isobutanol to meet the planned production from the Agri-Energy Facility. To facilitate the adoption of our technology at existing ethanol plants, we have entered into an exclusive alliance with ICM. We expect our relationships with entities such as Sasol Chemical Industries Limited (“Sasol”), Mansfield Oil Company, Toray Industries, Inc. (“Toray Industries”), the USAF, the U.S. Army, the U.S. Navy and LANXESS, Inc. (“LANXESS”), among others, to contribute to the development of new chemical and fuel market applications of our isobutanol. To enable the future integration of cellulosic feedstocks into our isobutanol production process, we have obtained an exclusive license from Cargill, Incorporated, to integrate its proprietary biocatalysts into our GIFT^® system. To accelerate the adoption of isobutanol as a platform molecule and to support the development of hydrocarbon products derived from our isobutanol, we have developed a hydrocarbon demonstration plant near Houston, Texas with South Hampton Resources.

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•

Experienced team with a proven track record. Our management team offers an exceptional combination of scientific, operational and managerial expertise and our CEO, Dr. Patrick Gruber, has spent over 20 years developing and successfully commercializing industrial biotechnology products. Across the Company, our employees have 400 combined years of biotechnology, synthetic biology and biobased product experience. Our employees have been inventors on over 300 patents and patent applications over the course of their careers. Our team members have played key roles in the commercialization of several successful, large-scale industrial biotechnology projects, including a sugar substitute sweetener, four organic acid technologies, an animal feed additive, monomers for plastics and biobased plastics and the first biologically derived high-purity monomer for the production of plastic at a world-scale production facility. As a result of their extensive experience, members of our management team play important roles in the industrial biotechnology industry at U.S. and international levels.

Concurrent Offering of Senior Note Units

Concurrently with this offering of common stock units, we are offering senior note units, with each senior note unit consisting of $1,000 principal amount of 2013 Notes and warrants to purchase shares of our common stock (or a total of $ aggregate principal amount of 2013 Notes and warrants to purchase up to shares of our common stock if the underwriter for the concurrent offering of senior note units exercises in full its option to purchase such additional securities) (and the common stock issuable from time to time upon exercise of each of the warrants) pursuant to a separate prospectus supplement. This offering of common stock units is not contingent upon the concurrent offering of senior note units, and the concurrent offering of senior note units is not contingent upon this offering of common stock units. The warrants offered in the concurrent offering of senior note units are expected to have a materially higher exercise price compared to the warrants offered hereby, but are otherwise expected to be substantially similar.

We expect to raise approximately $ million in aggregate net proceeds from the two offerings, after deducting underwriting discounts and commissions and estimated offering expenses. However, amounts sold in each offering may increase or decrease based on market conditions relating to a particular security. We cannot assure you that we will complete the concurrent senior note unit offering. Unless we specifically state otherwise, the information in this prospectus supplement assumes the completion of the concurrent senior note unit offering, that the underwriter for the concurrent senior note unit offering does not exercise its option to purchase additional 2013 Notes or warrants and that the underwriter for this common stock unit offering does not exercise its option to purchase additional common stock or warrants.

Certain Relationships

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Our Corporate Information

We were incorporated in Delaware in June 2005 under the name Methanotech, Inc. and filed an amendment to our certificate of incorporation changing our name to Gevo, Inc. on March 29, 2006. Our principal executive offices are located at 345 Inverness Drive South, Building C, Suite 310, Englewood, Colorado 80112, and our telephone number is (303) 858-8358. We maintain an internet website at www.gevo.com. Information contained in or accessible through our website does not constitute part of this prospectus supplement or the accompanying prospectus.

Information Regarding Liquidity

From inception to September 30, 2013, we have funded our operations primarily through equity offerings, issuances of debt, borrowings under our secured debt financing arrangements and revenues earned primarily from the sale of ethanol and related products. Our cash and cash equivalents at September 30, 2013 totaled $25.7 million which is primarily being used for the following: (i) operating activities and startup production of isobutanol at our Agri-Energy Facility; (ii) operating activities at our corporate headquarters in Colorado, including research and development work; (iii) capital improvements primarily associated with our Agri-Energy Facility; (iv) costs associated with optimizing isobutanol production technology; (v) costs associated with the ongoing litigation with Butamax Advanced Biofuels LLC (“Butamax”), a joint venture between British Petroleum (“BP”), E.I. du Pont de Nemours and Company (“DuPont”) and BP Biofuels; and (vi) repayment of debt obligations. Based on our current plans, we anticipate capital expenditures necessary to complete the retrofit of the Agri-Energy Facility will be significantly lower than the capital expenditures of $49.5 million incurred in fiscal year 2012 for this project. We believe that actions taken during 2012 to reduce ongoing litigation expenses and other operating expenses will continue to reduce our 2013 operating expenses from fiscal year 2012 levels. We also have the ability to further limit cash spending associated with the foregoing activities, including limiting the usage of cash associated with research and development activities or delaying the timing of capital improvements, based on then-current facts and circumstances. Notwithstanding our ability to further reduce our monthly cash usage, based on our current planned level of operations and anticipated growth, we believe that cash and cash equivalents on hand at September 30, 2013, will provide sufficient funds for ongoing operations for the remainder of 2013. This includes the cash needed to fund necessary capital expenditures, working capital requirements and debt obligations (including $3.6 million of principal payments in the fourth quarter of 2013). We believe we have the financial resources to operate into the first quarter of 2014. Based on current estimates, additional capital will be required for us to continue to meet ongoing operational and working capital requirements past the first quarter of 2014 and to finance the retrofit of incremental isobutanol production capacity including further expansion of our Agri-Energy Facility.

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The Offering

Common stock offered by us

shares of common stock.

Warrants offered by us

Warrants to purchase up to shares of common stock. The warrants will be exercisable during the period commencing from the date of original issuance and ending on December , 2018, the expiration date of the warrants, at an exercise price of $ per share of common stock. This prospectus also relates to the offering of the shares of common stock issuable upon exercise of the warrants. The exercise price of the warrants and the number of shares into which the warrants may be exercised are subject to adjustment in certain circumstances.

Common stock outstanding after this offering

shares of common stock.⁽¹⁾

Over-allotment option

Limitation on ownership of warrants

Any exercise notice with respect to the warrants delivered by a holder will be deemed automatically not to have been so delivered by such holder to the extent, but only to the extent, that delivery of shares of our common stock or any other security otherwise deliverable upon such exercise would result in such holder having a “beneficial ownership,” as determined in accordance with Section 13(d) of the Exchange Act and the rules thereunder (“Beneficial Ownership”), of our common stock or any other class of any equity security (other than an exempted security) that is registered pursuant to Section 12 of the Exchange Act (a “Class”) in excess of 19.999% of the number of outstanding shares of our common stock or such Class (the “19.999% Ownership Limitation”).

Notwithstanding the foregoing, during any period of time in which a holder’s Beneficial Ownership of our common stock or any other Class is less than 10%, any exercise notice with respect to the warrants delivered by a holder will be deemed automatically not to have been so delivered by such holder to the extent, but only to the extent, that delivery of shares of our common stock or any other security otherwise deliverable upon such conversion or exercise would result in such holder having a Beneficial Ownership of our common stock or any other Class in excess of 9.999% of the number of outstanding shares of our common stock or such Class (the “9.999% Ownership Limitation”).

Notwithstanding the foregoing, during any period of time in which a holder’s Beneficial Ownership of our common stock or any other Class is less than 5%, any exercise notice with respect

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to the warrants delivered by a holder will be deemed automatically not to have been so delivered by such holder to the extent, but only to the extent, that delivery of shares of our common stock or any other security otherwise deliverable upon such exercise would result in such holder having a Beneficial Ownership of our common stock or any other Class in excess of 4.999% of the number of outstanding shares of our common stock or such Class (the “4.999% Ownership Limitation”).

By written notice to us, any holder may from time to time increase or decrease either or both of the 9.999% Ownership Limitation or the 4.999% Ownership Limitation to any other percentage not in excess of the 19.999% Ownership Limitation; provided that any such increase will not be effective until the 65th day after such notice is delivered to us.

Use of proceeds

We expect the net proceeds from this offering to be approximately $ million (or $ million if the underwriter exercises in full its option to purchase additional shares of common stock and warrants) after deducting underwriting discounts and commissions, as described in “Underwriting,” and estimated offering expenses payable by us. We currently intend to use the net proceeds from this offering to fund the cash consideration payable to ramp up startup production and sales of isobutanol at the Agri-Energy Facility. We may also use a portion of the net proceeds of this offering to fund working capital and other general corporate purposes, which may include paying off certain of our long-term debt obligations and expenses associated with litigation.

As of the date of this prospectus supplement, we cannot specify with certainty all of the particular uses of the proceeds from this offering. Accordingly, we will retain broad discretion over the use of such proceeds. Pending the use of the net proceeds from this offering as described above, we intend to invest the net proceeds in demand deposit accounts. See “Use of Proceeds” on page S-59 of this prospectus supplement.

NASDAQ Global Market symbol

“GEVO”. The warrants are not and will not be listed for trading on the NASDAQ Global Market, or any other securities exchange.

Transfer Agent and Warrant Agent

American Stock Transfer & Trust Company

Risk factors

This investment involves a high degree of risk. See “Risk Factors” beginning on page S-14 of this prospectus supplement for a discussion of factors you should carefully consider before deciding to invest in our securities.

Concurrent offering of senior note units

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total of $ aggregate principal amount of 2013 Notes and warrants to purchase up to shares of our common stock if the underwriter for the concurrent offering of senior note units exercises in full its option to purchase such additional securities) (and the common stock issuable from time to time upon exercise of each of the warrants) pursuant to a separate prospectus supplement. This offering of common stock units is not contingent upon the concurrent offering of senior note units, and the concurrent offering of senior note units is not contingent upon this offering of common stock units. The warrants offered in the concurrent offering of senior note units are expected to have a materially higher exercise price compared to the warrants offered hereby, but are otherwise expected to be substantially similar.

⁽¹⁾The number of shares of our common stock to be outstanding immediately after the closing of this offering is based on 47,166,947 shares of common stock outstanding as of November 30, 2013 and excludes, as of that date:

•

2,933,706 shares of common stock issuable upon the exercise of outstanding stock options at a weighted average exercise price of $5.19 per share;

•

1,239,998 shares of common stock issuable upon the exercise of outstanding common stock warrants at a weighted average price of $4.57 per share;

•

3,199,640 shares of common stock available for future grant under our 2010 Stock Incentive Plan (as amended, the “2010 Plan”);

•

1,205,568 shares of common stock available for issuance pursuant to our Employee Stock Purchase Plan;

•

9,562,807 shares of common stock issuable upon conversion of the Company’s outstanding 7.5% convertible senior notes due 2022 (the “2012 Notes”), at the conversion rate in effect on November 30, 2013 (which amount includes 4,837,293 shares of common stock issuable in full satisfaction of the Coupon Make-Whole Payments (as defined in the applicable indenture) due in connection therewith);

•

shares of common stock issuable upon the exercise of the warrants offered hereby; and

•

shares of common stock reserved for issuance upon conversion of the 2013 Notes and exercise of the corresponding warrants offered in the concurrent senior note unit offering (including shares of common stock issuable in full satisfaction of the Coupon Make-Whole Payments due in connection therewith).

Unless otherwise stated, all information in this prospectus assumes no exercise of the underwriter’s over-allotment option.

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Summary Financial Information

In the tables below, we provide you with a summary of our historical consolidated financial information. The information is only a summary, and you should read it together with the financial information incorporated by reference in this document. See “Incorporation of Certain Documents by Reference” on page S-81 of this prospectus supplement and “Where You Can Find Additional Information” on page S-81 of this prospectus supplement. The consolidated statements of operations data for the years ended December 31, 2010, 2011 and 2012 is derived from our audited financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2012, as amended, and incorporated by reference herein. The consolidated balance sheet data as of September 30, 2013 and consolidated statements of operations data for the three and nine months ended September 30, 2012 and 2013 is derived from our unaudited quarterly financial statements included in our Quarterly Report on Form 10-Q for the three months ended September 30, 2013 and incorporated by reference herein. These unaudited financial statements have been prepared on a basis consistent with our audited financial statements and include, in the opinion of management, all adjustments, consisting only of normal recurring adjustments, necessary for the fair statement of the financial information in those statements.

Our consolidated subsidiary Agri-Energy, LLC, a Minnesota limited liability company (“Agri-Energy”), commenced the retrofit of the Agri-Energy Facility in 2011 and commenced initial startup operations for the production of isobutanol at this facility in May 2012. In September 2012, we made the strategic decision to pause isobutanol production at the Agri-Energy Facility for a period of time while we focused on optimizing specific parts of our technology to further enhance isobutanol production rates.

We have since resumed the production of isobutanol at the Agri-Energy Facility and plan to continue producing isobutanol on an integrated production basis throughout the rest of 2013 with the objective of testing production run rates and then further ramping up production toward nameplate capacity in 2014. Following our acquisition of Agri-Energy on September 22, 2010, we began recording revenue from the sale of ethanol and related products. Because the production of ethanol is not our intended business, we will continue to report as a development stage company until we begin to generate significant revenue from the sale of isobutanol or other products that are or will become our intended business. Accordingly, the historical operating results of Agri-Energy and the operating results reported during the retrofit to isobutanol production will not be indicative of future operating results for Agri-Energy once full-scale isobutanol production commences. For purposes of the disclosure contained in this section, “the company,” “we,” “us” and “our” refer to Gevo, Inc. and Gevo Development, LLC (“Gevo Development”) as the context requires, and include Agri-Energy following the completion of our acquisition on September 22, 2010.

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Consolidated statements of operations data:	Years Ended December 31,									Three Months Ended September 30,						Nine Months Ended September 30,
Consolidated statements of operations data:	2010⁽¹⁾			2011			2012			2012			2013			2012			2013
Revenues:
Ethanol sales and related products	$	14,765,000		$	63,742,000		$	19,908,000		$	—		$	—		$	19,908,000		$	—
Grant, research and development program revenue and other revenue		1,631,000			807,000			4,477,000			562,000			1,127,000			2,553,000			6,529,000

Total revenues		16,396,000			64,549,000			24,385,000			562,000			1,127,000			22,461,000			6,529,000

Cost of goods sold		(13,446,000	)		(60,588,000	)		(32,410,000	)		(6,079,000	)		(4,746,000	)		(29,599,000	)		(12,865,000	)

Gross (loss) margin		2,950,000			3,961,000			(8,025,000	)		(5,517,000	)		(3,619,000	)		(7,138,000	)		(6,336,000	)

Operating expenses:
Research and development		(14,820,000	)		(19,753,000	)		(19,431,000	)		(5,401,000	)		(5,476,000	)		(15,079,000	)		(16,280,000	)
Selling, general and administrative		(23,643,000	)		(28,901,000	)		(43,981,000	)		(13,508,000	)		(6,668,000	)		(36,175,000	)		(19,897,000	)

Total operating expenses		(38,463,000	)		(48,654,000	)		(63,412,000	)		(18,909,000	)		(12,144,000	)		(51,254,000	)		(36,177,000	)

Loss from operations		(35,513,000	)		(44,693,000	)		(71,437,000	)		(24,426,000	)		(15,763,000	)		(58,392,000	)		(42,513,000	)
Other (expense) income:
Interest expense	$	(2,374,000	)	$	(3,577,000	)	$	(6,338,000	)	$	(2,624,000	)	$	(1,733,000	)	$	(4,161,000	)	$	(7,321,000	)
Gain from change in fair value of embedded derivative		—			—			17,000,000			15,000,000			1,587,000			15,000,000			2,280,000
Loss from extinguishment of debt		—			—			—			—			—			—			(2,038,000	)
Interest and other income (expense)		108,000			85,000			63,000			(1,000	)		24,000			18,000			115,000
Loss from change in fair value of warrant liabilities		(2,333,000	)		(29,000	)		—			—			—			—			—

Other income (expense) — net		(4,599,000	)		(3,521,000	)		10,725,000			12,375,000			(122,000	)		10,857,000			(6,964,000	)

Net loss		(40,112,000	)		(48,214,000	)		(60,712,000	)		(12,051,000	)		(15,885,000	)		(47,535,000	)		(49,477,000	)

Deemed dividend — amortization of beneficial conversion feature on Series D-1 convertible preferred stock		(2,778,000	)		(1,094,000	)		—			—			—			—			—

Net loss attributable to Gevo, Inc. common stockholders	$	(42,890,000	)	$	(49,308,000	)		(60,712,000	)	$	(12,051,000	)	$	(15,885,000	)	$	(47,535,000	)	$	(49,477,000	)

Net loss per share of common stock attributable to Gevo, Inc. stockholders, basic and diluted	$	(37.44	)	$	(2.15	)	$	(1.86	)	$	(0.31	)	$	(0.34	)	$	(1.56	)	$	(1.14	)

Weighted-average number of common shares used in computing net loss per share of common stock, basic and diluted		1,145,500			22,909,916			32,619,091			38,547,441			46,052,867			30,374,378			43,492,291

⁽¹⁾Since Agri-Energy was acquired on September 22, 2010, our consolidated results of operations for the year ended December 31, 2010 include the results of operations of Agri-Energy from September 23, 2010 to the period end date.

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	As of September 30, 2013
Consolidated balance sheet data:	Actual			As Adjusted⁽¹⁾	As Further Adjusted⁽²⁾
Cash and cash equivalents	$	25,661,000		$	$
Total assets		117,129,000
2012 Notes, net of change in fair value of embedded derivative and debt discount		14,815,000
2013 Notes		—
Secured long-term debt, including current portion, net of debt discounts		17,909,000
Total liabilities		52,366,000
Accumulated deficit		(244,824,000	)
Total stockholders’ equity		64,763,000

⁽¹⁾The as adjusted consolidated balance sheet data gives effect to this offering and the application of the net proceeds, after deducting underwriter discounts and commissions and estimated offering expenses, therefrom as set forth under “Use of Proceeds.”

⁽²⁾The as further adjusted consolidated balance sheet data gives effect to the concurrent offering of senior note units and the application of the net proceeds, after deducting underwriter discounts and commissions and estimated offering expenses, therefrom as set forth under “Use of Proceeds.” Estimated offering expenses have been reflected in as further adjusted total assets, as such amounts will be capitalized and amortized over the life of the 2013 Notes. Underwriter discounts and commissions have been reflected as a reduction in the as further adjusted 2013 Notes, as such amounts are considered a debt discount and will be amortized over the life of the 2013 Notes. The as further adjusted consolidated balance sheet data also gives effect to the repayment of $5.1 million in outstanding long-term debt obligations owed to TriplePoint Capital LLC (“TriplePoint”). This offering of common stock units is not contingent upon the concurrent offering of senior note units, and the concurrent offering of senior note units is not contingent upon this offering of common stock units.

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RISK FACTORS

An investment in our securities involves a substantial risk of loss. You should carefully consider these risk factors, together with all of the other information included or incorporated by reference in this prospectus supplement and the accompanying prospectus, as modified and superseded pursuant to Rule 412 under the Securities Act of 1933, as amended (the “Securities Act”), before you decide to invest in our securities. The occurrence of any of the following risks could harm our business. In that case, the trading price of our common stock and warrants could decline, and you may lose all or part of your investment. Additional risks and uncertainties not presently known to us or that we currently believe are immaterial may also impair our business operations and our liquidity. You should also refer to the other information contained in this prospectus supplement and the accompanying prospectus or incorporated by reference herein or therein, including our financial statements and the notes to those statements and the information set forth under the heading “Cautionary Note Regarding Forward-Looking Statements.”

Certain Risks Relating to Owning Our Securities.

We have broad discretion in the use of the net proceeds from this offering and the concurrent offering of senior note units, if any, and may not use them effectively, which could cause the value of your investment to decline.

Although we currently intend to use the net proceeds from this offering and the concurrent offering of senior note units, if any, in the manner described in “Use of Proceeds” elsewhere in this prospectus supplement, we will have broad discretion in the application of the net proceeds of this offering and the concurrent offering of senior note units, if any. You will not have the opportunity to influence our decisions on how to use our net proceeds from this offering and the concurrent offering of senior note units, if any. Our failure to apply these net proceeds effectively could affect our ability to continue to develop and sell our products and grow our business, which could cause the value of your investment to decline.

We will incur significant indebtedness when we sell the 2013 Notes and we may incur additional indebtedness in the future. The indebtedness created by the sale of the 2013 Notes and any future indebtedness we incur exposes us to risks that could adversely affect our business, financial condition and results of operations.

Concurrently with this offering of common stock units, we are offering senior note units, with each senior note unit consisting of $1,000 principal amount of 2013 Notes and warrants to purchase shares of our common stock. As of September 30, 2013, the aggregate amount of the outstanding principal and final payments under the Amended Agri-Energy Loan Agreement (as defined below) was approximately $18.9 million. In addition, we incurred $45.0 million of senior indebtedness when we sold the 2012 Notes in July 2012, of which $26.9 million is outstanding as of September 30, 2013. We will incur an additional $ million of senior indebtedness when we sell the senior note units, or $ million of senior indebtedness if the underwriter for the concurrent offering of senior note units exercises in full its option to purchase additional 2013 Notes. While the indenture governing the 2013 Notes will limit our ability to incur additional indebtedness, incur liens and issue preferred stock, our subsidiaries may incur long-term indebtedness or additional working capital lines of credit to meet future financing needs. The indenture governing the 2013 Notes will also allow us to incur an unlimited amount of certain unsecured indebtedness, provided that such indebtedness, among other things, matures at least 91 days after December 1, 2018. Furthermore, on or after December 4, 2018, the indenture will no longer contain any restrictions on our ability to incur indebtedness, issue preferred stock or create liens. Our indebtedness could have significant negative consequences for our business, results of operations and financial condition, including:

•

increasing our vulnerability to adverse economic and industry conditions;

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•

limiting our ability to obtain additional financing;

•

requiring the dedication of a substantial portion of our cash flow from operations to service our indebtedness, thereby reducing the amount of our cash flow available for other purposes;

•

limiting our flexibility in planning for, or reacting to, changes in our business; and

•

placing us at a possible competitive disadvantage with less leveraged competitors and competitors that may have better access to capital resources.

We cannot assure you that we will continue to maintain sufficient cash reserves or that our business will generate cash flow from operations at levels sufficient to permit us to pay principal, premium, if any, and interest on our indebtedness, or that our cash needs will not increase. If we are unable to generate sufficient cash flow or otherwise obtain funds necessary to make required payments, or if we fail to comply with the various requirements of our existing indebtedness, the 2013 Notes or any other indebtedness which we may incur in the future, we would be in default, which would permit the holders of the 2012 Notes and the 2013 Notes (together, the “Convertible Notes”) and such other indebtedness to accelerate the maturity of the Convertible Notes and such other indebtedness and could cause defaults under the Convertible Notes and such other indebtedness. Any default under the Convertible Notes or such other indebtedness could have a material adverse effect on our business, results of operations and financial condition.

We and our subsidiaries may incur substantially more debt or take other actions which would intensify the risks discussed above.

While the indenture governing the 2013 Notes will limit our ability to incur additional indebtedness, incur liens and issue preferred stock, our current and future subsidiaries may incur substantial additional debt in the future, subject to certain limitations in the indenture governing the 2013 Notes and the agreements governing our secured indebtedness with TriplePoint. Under the terms of the indenture governing the 2013 Notes, our subsidiaries will not be restricted from incurring additional indebtedness, incurring liens or issuing preferred stock. The indenture governing the 2013 Notes will also allow us to incur an unlimited amount of certain unsecured indebtedness, provided that such indebtedness, among other things, matures at least 91 days after December 1, 2018. Furthermore, on or after December 4, 2018, the indenture will no longer contain any restrictions on our ability to incur indebtedness, issue preferred stock or create liens. In addition, the indenture governing the 2013 Notes will not limit our or our subsidiaries’ ability to take a number of other actions, including the ability to pay dividends, purchase our securities, make investments and sell assets, that could have the effect of diminishing our ability to make payments on the 2013 Notes when due. Such actions may, however, be limited by the terms of the agreements governing our secured indebtedness with TriplePoint. In addition, the ability of our subsidiaries to incur such indebtedness may be adversely affected by our inability, as a result of the covenants in the indenture governing the 2013 Notes, to guarantee such obligations. If new debt is added to our or any of our subsidiaries’ debt levels, the risks described in this “Certain Risks Relating to Owning our Securities” section could intensify.

Our stock price may be volatile, and your investment in our securities could suffer a decline in value.

The market price of shares of our common stock has experienced significant price and volume fluctuations. For example, since February 19, 2011, when we became a public company, the closing sales price for one share of our common stock has reached a high of $26.36 and a low of $1.32. We expect that the market price of our common stock, as well as the general level of interest rates and our credit quality, will significantly affect the market price of the Convertible Notes. This may result in significantly greater volatility in the trading value of the Convertible Notes than would be expected for nonconvertible debt securities we may issue.

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We cannot predict whether the price of our common stock or interest rates will rise or fall. A variety of factors may have a significant effect on our stock price, including:

•

actual or anticipated fluctuations in our financial condition and operating results;

•

the position of our cash and cash equivalents;

•

actual or anticipated changes in our growth rate relative to our competitors;

•

actual or anticipated fluctuations in our competitors’ operating results or changes in their growth rate;

•

announcements of technological innovations by us, our partners or our competitors;

•

announcements by us, our partners or our competitors of significant acquisitions, strategic partnerships, joint ventures or capital commitments;

•

the entry into, modification or termination of licensing arrangements, marketing arrangements, and/or research, development, commercialization, supply, off-take or distribution arrangements;

•

our ability to consistently produce commercial quantities of isobutanol at the Agri-Energy Facility and ramp up production to nameplate capacity;

•

additions or losses of customers;

•

additions or departures of key management or scientific personnel;

•

competition from existing products or new products that may emerge;

•

issuance of new or updated research reports by securities or industry analysts;

•

fluctuations in the valuation of companies perceived by investors to be comparable to us;

•

litigation involving us, our general industry or both;

•

disputes or other developments related to proprietary rights, including patents, litigation matters and our ability to obtain patent protection for our technologies;

•

changes in existing laws, regulations and policies applicable to our business and products, including the Renewable Fuel Standard (“RFS”) program, and the adoption of or failure to adopt carbon emissions regulation;

•

announcements or expectations of additional financing efforts;

•

sales of our common stock or equity-linked securities, such as warrants, by us or our stockholders;

•

share price and volume fluctuations attributable to inconsistent trading volume levels of our shares;

•

general market conditions in our industry; and

•

general economic and market conditions, including the recent financial crisis.

Furthermore, the stock markets have experienced extreme price and volume fluctuations that have affected and continue to affect the market prices of equity securities of many companies. These fluctuations often have been unrelated or disproportionate to the operating performance of those companies. These broad market and industry fluctuations, as well as general economic, political and market conditions such as recessions, interest rate changes or international currency fluctuations, may negatively impact the market price of shares of our common stock, regardless of our operating

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performance, and cause the value of your investment to decline. Because the Convertible Notes are convertible into our common stock and the warrants are exercisable into our common stock, volatility or a reduction in the market price of our common stock could have an adverse effect on the trading price of the Convertible Notes and the warrants. Holders who receive common stock upon conversion of the Convertible Notes or exercise of the warrants will also be subject to the risk of volatility and a reduction in the market price of our common stock. In addition, the existence of the Convertible Notes and the warrants may encourage short selling in our common stock by market participants because the conversion of the Convertible Notes or exercise of the warrants could depress the price of our common stock.

Additionally, in the past, companies that have experienced volatility in the market price of their stock have been subject to securities class action litigation or other derivative shareholder lawsuits. We may be the target of this type of litigation in the future. Securities litigation against us could result in substantial costs and divert our management’s attention from other business concerns, which could seriously harm our business regardless of the outcome.

The price of our common stock could also be affected by possible sales of common stock by investors who view the Convertible Notes or warrants as a more attractive means of equity participation in us and by hedging or arbitrage activity involving our common stock that we expect to increase as a result of the issuance of the 2013 Notes. The hedging or arbitrage could, in turn, affect the trading prices of the Convertible Notes and warrants, or any common stock that holders receive upon conversion of the Convertible Notes or exercise of the warrants.

Sales of a substantial number of shares of our common stock or securities linked to our common stock, such as the Convertible Notes and warrants, in the public market could occur at any time. These sales, or the perception in the market that such sales may occur, could reduce the market price of our common stock.

Based solely on Schedules 13D and 13G that have been filed with the SEC, stockholders as of November 30, 2013 who beneficially own more than 5% of our outstanding common stock, which consists of five stockholders, collectively have beneficial ownership of approximately 39% of our outstanding common stock, not taking into account shares of common stock or warrants that certain of our existing stockholders or their respective affiliates, may purchase in this offering and/or the concurrent offering of senior note units. If one or more of them were to sell a substantial portion of the shares they beneficially hold, it could cause our stock price to decline. Moreover, certain holders of our outstanding common stock (including shares of our common stock issuable upon the exercise of outstanding warrants) have rights, subject to some conditions, to require us to file registration statements covering their shares and to include their shares in registration statements that we may file for ourselves or other stockholders.

We may not have the ability to pay interest on the Convertible Notes or to repurchase or redeem the Convertible Notes.

The 2013 Notes bear interest at a rate of % per year, payable in cash semi-annually in arrears on June 1 and December 1 of each year, beginning on June 1, 2014. The 2012 Notes, which had a principal balance of $26.9 million at September 30, 2013, bear interest at a rate of 7.5% per year, payable in cash semi-annually in arrears on January 1 and July 1 of each year. If a Fundamental Change (as defined in the applicable indenture) occurs, holders of the Convertible Notes may require us to repurchase, for cash, all or a portion of their Convertible Notes. It would be a Fundamental Change under the indentures governing Convertible Notes if, among other things, our common stock is not listed on a national securities exchange. The failure by us to meet the minimum listing requirements for the exchange could result in our common stock being delisted from the exchange and trigger a Fundamental Change. In such

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circumstance we would be required to offer to repurchase the Convertible Notes at 100% plus accrued and unpaid interest, to, but not including, the repurchase date. If we elect to redeem the Convertible Notes prior to their maturity, the redemption price of any Convertible Notes redeemed by us will be paid for in cash. Our ability to pay the interest on the Convertible Notes, to repurchase or redeem the Convertible Notes, to refinance our indebtedness and to fund working capital needs and planned capital expenditures depends on our ability to generate cash flow in the future. To some extent, this is subject to general economic, financial, competitive, legislative and regulatory factors and other factors that are beyond our control. We cannot assure you that we will maintain sufficient cash reserves or that our business will generate cash flow from operations at levels sufficient to permit us to pay the interest on the Convertible Notes, to repurchase or redeem the Convertible Notes or to pay any cash amounts that may become due upon conversion of the Convertible Notes, or that our cash needs will not increase. In addition, any such repurchase or redemption of the Convertible Notes, even if such action would be in our best interests, may result in a default under the agreements governing our secured indebtedness with TriplePoint unless we are able to obtain TriplePoint’s consent prior to the taking of such action.

Our failure to repurchase tendered Convertible Notes at a time when the repurchase is required by the indentures governing the Convertible Notes would constitute a default under the Convertible Notes and would permit holders of the Convertible Notes to accelerate our obligations under the Convertible Notes. Such default may also lead to a default under the agreements governing any of our current and future indebtedness. If the repayment of the related indebtedness were to be accelerated after any applicable notice or grace periods, we may not have sufficient funds to repay such indebtedness and repurchase the Convertible Notes or make cash payments upon conversions thereof.

If we are unable to generate sufficient cash flow from operations in the future to service our indebtedness and meet our other needs, we may have to refinance all or a portion of our indebtedness, obtain additional funds through public or private debt or equity financings, reduce expenditures or sell assets that we deem necessary to our business. Our ability to take some or all of these actions will be subject to certain limitations in the indenture governing the 2013 Notes and the agreements governing our secured indebtedness with TriplePoint, and we cannot assure you that any of these measures would be possible or that any additional financing could be obtained on favorable terms, or at all. The inability to obtain additional financing on commercially reasonable terms could have a material adverse effect on our financial condition, which could cause the value of your investment to decline. Additionally, if we were to conduct a public or private offering of securities, any new offering would be likely to dilute our stockholders’ equity ownership.

We may not be permitted, by the agreements governing our secured indebtedness, to repurchase the Convertible Notes.

If a Fundamental Change occurs, the holders of the Convertible Notes may require us to repurchase all or a portion of their Convertible Notes for cash at a repurchase price equal to 100% of the principal amount of the Convertible Notes to be repurchased, plus any accrued and unpaid interest to, but excluding, the repurchase date. However, the agreements governing our secured indebtedness with TriplePoint prohibit us from paying, repurchasing or redeeming the Convertible Notes or any amounts payable in connection with a Fundamental Change. In the event that a Fundamental Change occurs at a time when we are prohibited from repurchasing the Convertible Notes, we would need to seek the consent of TriplePoint to repurchase the Convertible Notes from the holders or we would otherwise be risking an event of default under our agreements with TriplePoint. If we were unable to obtain such consent, compliance with the terms of the Convertible Notes would trigger an event of default under our indebtedness with TriplePoint.

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The indenture governing the 2013 Notes will contain negative covenants that, subject in each case to certain exceptions, generally will limit our, but not our subsidiaries’, ability to incur indebtedness and liens.

The indenture governing the 2013 Notes will contain negative covenants that will prohibit us, but not our subsidiaries, from creating, incurring, issuing, assuming, guaranteeing or otherwise becoming liable for any new indebtedness, except for certain permitted indebtedness, and will restrict our, but not our subsidiaries’, ability to create, incur, assume, or suffer to exist any new liens, except for certain permitted liens. As a result of these covenants, for so long as any of the 2013 Notes are outstanding, the maximum amount of senior indebtedness that we will be permitted to have outstanding at any one time (including pursuant to the Amended Agri-Energy Loan Agreement) will be $15.0 million. The indenture governing the 2013 Notes will also permit us to incur an unlimited amount of additional indebtedness, provided that such indebtedness, among other things, matures at least 91 days after December 1, 2018. Furthermore, on or after December 4, 2018, the indenture will no longer contain any restrictions on our ability to incur indebtedness, issue preferred stock or create liens. Our subsidiaries will not be subject to these covenants and may incur additional secured and unsecured, short-term or long-term indebtedness or additional working capital lines of credit to meet future financing needs. However, the ability of our subsidiaries to incur such indebtedness may be adversely affected by the limitations on our ability, as a result of the covenants, to guarantee such obligations. These covenants could limit our ability to operate our business and to finance our future operations and capital needs, including our ability to access and/or Retrofit existing ethanol facilities and to pursue other business activities that may be in our interest.

Our ability to comply with these covenants can be affected by events beyond our control, including prevailing economic, financial and industry conditions. Should market conditions become depressed in the future, we may have to request amendments or waivers to the covenants. Any such amendments or waivers may be costly to obtain and there can be no assurance that we will be able to obtain such relief on terms that are favorable or acceptable to us or at all.

If we fail to comply with these covenants and are unable to obtain a waiver of such restrictions, an event of default could occur under the indenture governing the 2013 Notes, which could result in the acceleration of the maturity of the 2013 Notes and cause such indebtedness to become immediately due and payable. Any such event of default could also trigger events of default under the indenture governing our 2012 Notes and the Amended Agri-Energy Loan Agreement, which could result in the acceleration of the maturity of the 2012 Notes and an acceleration of the maturity of amounts owed under the Amended Agri-Energy Loan Agreement. We cannot assure you that our assets or cash flow would be sufficient to fully repay borrowings under our outstanding debt instruments if accelerated upon an event of default or that we would be able to find alternative financing. Even if we could obtain alternative financing, it might not be on terms that are favorable or acceptable to us. In addition, any such payment of the Convertible Notes upon acceleration, even if such action would be in our best interests, may result in a default under the agreements governing our current indebtedness with TriplePoint unless we are able to obtain TriplePoint’s consent prior to the taking of such action. An event of default under any the agreements governing our indebtedness could have a material adverse effect on our financial condition, which could cause the value of your investment to decline.

Future issuances of our common stock or instruments convertible or exercisable into our common stock, including in connection with conversions of Convertible Notes or exercise of warrants, may materially and adversely affect the price of our common stock, our warrants and the Convertible Notes and cause dilution to our existing stockholders.

In addition to the current offerings of common stock units and senior note units, we may obtain additional funds through public or private debt or equity financings in the near future, subject to certain limitations in the indenture governing the 2013 Notes and the agreements governing our secured indebtedness with TriplePoint. Other than lock-up provisions that apply for the first 90 days after the date of this prospectus supplement, subject to certain limitations in the indenture governing the 2013

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Notes and the agreements governing our secured debt with TriplePoint, we are not restricted from issuing additional shares of our common stock or other instruments convertible into our common stock. If we issue additional shares of common stock or instruments convertible into common stock, it may materially and adversely affect the price of our common stock and, in turn, the price of the warrants. In addition, the conversion of some or all of the Convertible Notes and/or exercise of our warrants may dilute the ownership interests of our stockholders, and any sales in the public market of any of our common stock issuable upon such conversion or exercise could adversely affect prevailing market prices of our common stock and warrants. Additionally, under the terms of the warrants, in the event that a warrant is exercised at a time when we do not have an effective registration statement covering the underlying shares of common stock on file with the SEC, such warrant must be net exercised, which will dilute the ownership interests of existing stockholders without any corresponding benefit to the Company of a cash payment for the exercise price of such warrant.

As of November 30, 2013, there were 9,562,807 shares of common stock issuable upon conversion of the outstanding 2012 Notes at the conversion rate in effect on November 30, 2013 (which amount includes 4,837,293 shares of common stock issuable in full satisfaction of the Coupon Make-Whole Payments due in connection therewith). If our stock price decreases, the number of shares we would be required to deliver in connection with the Coupon Make-Whole payments would increase. As of September 30, 2013, approximately $18.1 million in principal amount of the 2012 Notes has been converted in exchange for 3,179,608 shares of our common stock. The anticipated conversion of the remaining approximately $26.9 million in principal amount of 2012 Notes into shares of our common stock could depress the trading price of our common stock and warrants.

Holders of our Convertible Notes that elect to convert (i) some or all of their 2012 Notes prior to July 1, 2017, or (ii) some or all of their 2013 Notes on or after June 1, 2014 and prior to December 1, 2018 will be entitled to receive a Coupon Make-Whole Payment for the Convertible Notes being converted. We have the option to issue our common stock to any converting holder in lieu of making the Coupon Make-Whole Payment in cash. If we elect to issue our common stock for such payment, then the stock will be valued at 90% of the simple average of the daily volume weighted average prices of our common stock for the 10 trading days ending on and including the trading day immediately preceding the conversion date; subject, in the case of the 2013 Notes, to a minimum daily volume weighted average price of $ . Given that the agreements governing our secured indebtedness with TriplePoint prohibit us from paying, repurchasing or redeeming the Convertible Notes or making cash payments in respect of the Coupon Make-Whole Payment upon a conversion, we may be unable to make such payment in cash. As of September 30, 2013, we have issued 2,957,775 shares of our common stock in satisfaction of Coupon Make-Whole Payments due in connection with the conversion of the 2012 Notes. If we elect to issue additional shares of our common stock for such payments, this may cause significant additional dilution to our existing stockholders.

The issuance of share-based payment awards under our stock incentive plan may cause dilution to our existing stockholders and may affect the market price of our common stock.

We have used, and in the future we may continue to use, stock options, stock grants and other equity-based incentives, either pursuant to the 2010 Plan, or outside of the 2010 Plan, to provide motivation and compensation to our directors, officers, employees and key independent consultants. The award of any such incentives will result in an immediate and potentially substantial dilution to our existing shareholders and could result in a decline in the value of our stock price.

As of November 30, 2013, there were 2,933,706 shares subject to outstanding options that are or will become eligible for sale in the public market to the extent permitted by any applicable vesting requirements and Rules 144 and 701 under the Securities Act. The exercise of these options and the sale of the underlying shares of common stock and the sale of stock issued pursuant to stock grants may have

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an adverse effect upon the price of our common stock, which in turn may have an adverse effect upon the trading price of the warrants.

As of November 30, 2013, we have 5,571,286 shares of common stock reserved for issuance under the 2010 Plan and our Employee Stock Purchase Plan. These shares can be freely sold in the public market upon issuance and once vested.

We may pay vendors in stock as consideration for their services; this may result in additional costs and may cause dilution to our existing stockholders.

In order for us to preserve our cash resources, we may in the future pay vendors, including technology partners, in shares, warrants or options to purchase shares of our common stock rather than cash. Payments for services in stock may materially and adversely affect our stockholders by diluting the value of outstanding shares of our common stock. In addition, in situations where we agree to register the shares issued to a vendor, this will generally cause us to incur additional expenses associated with such registration.

We cannot assure our stockholders that our stock repurchase program will enhance long-term stockholder value, and stock repurchases could increase the volatility of the price of our common stock and will diminish our available cash.

In January 2013, our board of directors approved a stock repurchase program for up to $15.0 million of our common stock over a one-year period. We expect to fund any repurchases under the stock repurchase program with cash and cash equivalents on hand. The timing and actual number of shares repurchased will depend on a variety of factors including the timing of open trading windows, price, corporate and regulatory requirements, an assessment by management and our board of directors of cash availability and other market conditions. The program may be suspended or discontinued at any time without prior notice. Repurchases pursuant to our stock repurchase program could affect the price of our common stock and increase its volatility. The existence of our stock repurchase program could also cause the price of our common stock to be higher than it would be in the absence of such a program and could potentially reduce the market liquidity for our common stock. Additionally, repurchases under our stock repurchase program will diminish our cash reserves, which could impact our ability to further develop our technology, access and/or Retrofit additional facilities and service our indebtedness. There can be no assurance that any stock repurchases will enhance stockholder value because the market price of our common stock may decline below the levels at which we repurchased such shares. Any failure to repurchase shares after we have announced our intention to do so may negatively impact our reputation and investor confidence in us and may negatively impact our stock price. Although our stock repurchase program is intended to enhance long-term stockholder value, short-term stock price fluctuations could reduce the program’s effectiveness.

We are subject to anti-takeover provisions in our amended and restated certificate of incorporation, as amended (our “Certificate of Incorporation”), and amended and restated bylaws and under Delaware law that could delay or prevent an acquisition of the Company, even if the acquisition would be beneficial to our stockholders.

Provisions in our Certificate of Incorporation and our amended and restated bylaws may delay or prevent an acquisition of us. Among other things, our Certificate of Incorporation and amended and restated bylaws provide for a board of directors that is divided into three classes with staggered three-year terms, provide that all stockholder action must be effected at a duly called meeting of the stockholders and not by a consent in writing, and further provide that only our board of directors may call a special meeting of the stockholders. These provisions may also frustrate or prevent any attempts by our stockholders to replace or remove our current management by making it more difficult for stockholders to replace members of our board of directors, who are responsible for appointing the

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members of our management team. Furthermore, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the Delaware General Corporation Law, which prohibits, with some exceptions, stockholders owning in excess of 15% of our outstanding voting stock from merging or combining with us. Finally, our charter documents establish advance notice requirements for nominations for election to our board of directors and for proposing matters that can be acted upon at stockholder meetings. Although we believe these provisions together provide an opportunity to receive higher bids by requiring potential acquirers to negotiate with our board of directors, they would apply even if an offer to acquire the Company may be considered beneficial by some stockholders.

Concentration of ownership among our affiliates may prevent other stockholders from influencing significant corporate decisions and depress our stock price.

Our affiliates who held our common stock as of November 30, 2013 together control approximately 27% of our outstanding common stock, with a single stockholder, Khosla Ventures I, L.P. and its affiliates, controlling approximately 15% of our outstanding common stock, not taking into account shares of common stock and warrants sold in this offering or 2013 Notes and warrants sold in the concurrent offering of senior note units or the potential participation of certain of our directors, officers and existing stockholders in such offerings. If our affiliates or a group of our affiliates act together, they will be able to exert a significant degree of influence over our management and affairs and control matters requiring stockholder approval, including the election of directors and approval of mergers or other business combination transactions. The interests of this concentration of ownership may not always coincide with our interests or the interests of other stockholders. For instance, our affiliates, acting together, could cause us to enter into transactions or agreements that we would not otherwise consider. Similarly, this concentration of ownership may have the effect of delaying or preventing a change in control of the Company otherwise favored by our other stockholders and holders of warrants. This concentration of ownership could depress our stock price, which would in turn depress the trading price of the common stock and warrants.

If securities or industry analysts do not publish research or reports about our business, or publish negative reports about our business, our stock price and trading volume could decline. The trading market for our common stock will be influenced by the research and reports that securities or industry analysts publish about us or our business.

We do not have any control over these analysts. If one or more of the analysts who cover us downgrade our stock or change their opinion of our stock, our stock price would likely decline which in turn would likely cause a decline in the value of the warrants and the Convertible Notes. If one or more of these analysts cease coverage of the Company or fail to regularly publish reports on us, we could lose visibility in the financial markets, which could cause our stock price and the price of the warrants and Convertible Notes to decline or the trading volume of such securities to decline.

We do not anticipate paying cash dividends, and accordingly, stockholders must rely on stock appreciation for any return on their investment.

Under the terms of the Amended Agri-Energy Loan Agreement, subject to certain limited exceptions, Agri-Energy is only permitted to pay dividends if the following conditions are satisfied: (i) the retrofit of the Agri-Energy Facility is complete and the facility is producing commercial volumes of isobutanol, (ii) its net worth is greater than or equal to $10.0 million, and (iii) no event of default has occurred and is continuing under the agreement. Agri-Energy is also permitted to make dividends and distributions to Gevo, Inc. for certain defined purposes related to the Convertible Notes. Accordingly, even if we decide to pay cash dividends in the future, we may not be able to access cash generated by Agri-Energy if amounts are then outstanding pursuant to the Amended Agri-Energy Loan Agreement. We have never paid cash dividends on our common stock and we do not expect to pay cash dividends on our common stock at any time in the foreseeable future. The future payment of dividends directly depends upon our

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future earnings, capital requirements, financial requirements and other factors that our board of directors will consider. As a result, only appreciation of the price of our common stock, which may never occur, will provide a return to stockholders. Investors seeking cash dividends should not invest in our common stock.

We may not be able to comply with all applicable listing requirements or standards of the NASDAQ Global Market and NASDAQ could delist our common stock.

Our common stock is listed on the NASDAQ Global Market. In order to maintain that listing, we must satisfy minimum financial and other continued listing requirements and standards. There can be no assurances that we will be able to comply with applicable listing standards. In the event that our common stock is not eligible for quotation on another market or exchange, trading of our common stock could be conducted in the over-the-counter market or on an electronic bulletin board established for unlisted securities such as the Pink Sheets or the OTC Bulletin Board. In such event, it could become more difficult to dispose of, or obtain accurate price quotations for, our common stock, and there would likely be a reduction in our coverage by security analysts and the news media, which could cause the price of our common stock to decline further. In addition, it may be difficult for us to raise additional capital if we are not listed on a major exchange. Furthermore, it would be a Fundamental Change under the indentures governing the Convertible Notes if our common stock is not listed on a national securities exchange. In such circumstance we would be required to offer to repurchase the Convertible Notes at 100% plus accrued and unpaid interest, to, but not including, the repurchase date. Such offers would be prohibited by the agreements governing our secured indebtedness to TriplePoint.

Significant holders or beneficial holders of our common stock may not be permitted to exercise warrants that they hold.

The warrant agreement governing the warrants will prohibit a holder from exercising its warrants if doing so would result in such holder beneficially owning more than 19.999% of our common stock or any other Class. Furthermore, during any period in which a holder beneficially owns less than 10% of our common stock or any other Class, the warrant agreement will limit the ability of such holder to exercise its warrants if doing so would result in such holder beneficially owning more than 9.999% of our common stock or any other Class. Also, during any period in which a holder beneficially owns less than 5% of our common stock or any other Class, the warrant agreement will limit the ability of such holder to exercise its warrants if doing so would result in such holder beneficially owning more than 4.999% of our common stock or any other Class. As a result, you may not be able to exercise your warrants for shares of our common stock at a time when it would be financially beneficial for you to do so. In such circumstance you could seek to sell your warrants to realize value, but you may be unable to do so.

There is no public market for the warrants to purchase common stock being offered in this offering.

There is no established public trading market for the warrants being offered in this offering, and we do not expect a market to develop. In addition, we do not intend to apply for listing of the warrants on any securities exchange. Without an active market, the liquidity of the warrants will be limited.

Holders of our warrants will have no rights as a common stockholder until such holders exercise their warrants and acquire our common stock.

Until you acquire shares of our common stock upon exercise of your warrants, you will have no rights with respect to the shares of our common stock underlying such warrants. Upon exercise of your warrants, you will be entitled to exercise the rights of a common stockholder only as to matters for which the record date occurs after the exercise date.

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The exercise price for the warrants will not be adjusted for all dilutive events.

The exercise price for the warrants is subject to adjustment for certain events, including the issuance of stock dividends on our common stock and, in certain instances, the issuance of our common stock at a price per share less than the exercise price of the warrants. However, the exercise rate will not be adjusted for other events, including the issuance of certain rights, options or warrants, distributions of capital stock, indebtedness, or assets and cash dividends. Accordingly, an event that adversely affects the value of the warrants may occur, and that event may not result in an adjustment to the exercise price.

We may not be permitted by the agreements governing our secured indebtedness to repurchase the warrants, and we may not have the ability to do so.

Under certain circumstances, if an extraordinary transaction (as defined in the warrants) occurs, holders of the warrants may require us to repurchase, for cash, the remaining unexercised portion of such warrants for an amount of cash equal to the value of the warrant as determined in accordance with the Black Scholes option pricing model and the terms of the warrants. Our ability to repurchase the warrants depends on our ability to generate cash flow in the future. To some extent, this is subject to general economic, financial, competitive, legislative and regulatory factors and other factors that are beyond our control. We cannot assure you that we will maintain sufficient cash reserves or that our business will generate cash flow from operations at levels sufficient to permit us to repurchase the warrants. In addition, any such repurchase of the warrants may result in a default under the agreements governing our secured indebtedness with TriplePoint unless we are able to obtain TriplePoint’s consent prior to the taking of such action. If we were unable to obtain such consent, compliance with the terms of the warrants would trigger an event of default under our indebtedness with TriplePoint.

Certain Risks Relating to our Business and Strategy

We are a development stage company with a history of net losses, and we may not achieve or maintain profitability.

We have incurred net losses since our inception, including losses of $60.7 million, $48.2 million, $40.1 million, $15.9 million and $49.5 million during the years ended December 31, 2012, 2011 and 2010 and the three and nine months ended September 30, 2013, respectively. As of September 30, 2013, we had an accumulated deficit of $244.8 million. We expect to incur losses and negative cash flow from operating activities for the foreseeable future. We are a development stage company and, to date, our revenues from the sale of isobutanol and related products have been limited. Prior to September 2010, our revenues were primarily derived from government grants and cooperative agreements. From the completion of our acquisition of Agri-Energy in September 2010 until the commencement of our initial start-up operations for isobutanol production in May 2012, we had also generated revenue from the sale of ethanol and related products. Similarly, we may derive revenue from the sale of ethanol and related products during periods in which the production of isobutanol is temporarily paused and our management decides, based on the then-current economic conditions for the production and sale of ethanol, that the Agri-Energy Facility will be temporarily reverted to ethanol production. Additionally, we have generated limited revenue from the sale of products such as ATJ fuel produced from isobutanol that has been used for engine qualification and flight demonstration by the USAF and other branches of the United States military. Following the commencement of full-scale commercial production of isobutanol, we do not expect to generate significant future revenues from the sale of ethanol at the Agri-Energy Facility. If our existing grants and cooperative agreements are canceled prior to the expected end dates or we are unable to obtain new grants and cooperative agreements or our ATJ supply contracts are cancelled or we are unable to produce suitable ATJ material, our revenues could be adversely affected.

Furthermore, we expect to spend significant amounts on the further development and commercial implementation of our technology. We also expect to spend significant amounts acquiring and deploying additional equipment to attain final product specifications that may be required by future customers,

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acquiring or otherwise gaining access to additional ethanol plants and Retrofitting them for isobutanol production, on marketing, general and administrative expenses associated with our planned growth and on management of operations as a public company. In addition, the cost of preparing, filing, prosecuting, maintaining and enforcing patent, trademark and other intellectual property rights and defending ourselves against claims by others that we may be violating their intellectual property rights may be significant.

In particular, over time, the costs of our litigation with Butamax have been and may continue to be significant. Furthermore, over time, costs related to defending the validity of our issued patents and challenging the validity of the patents of others at the U.S. Patent and Trademark Office (“USPTO”) have also been and may continue to be significant. As a result, even if our revenues increase substantially, we expect that our expenses will exceed revenues for the foreseeable future. We do not expect to achieve profitability during the foreseeable future, and may never achieve it. If we fail to achieve profitability, or if the time required to achieve profitability is longer than we anticipate, we may not be able to continue our business. Even if we do achieve profitability, we may not be able to sustain or increase profitability on a quarterly or annual basis.

We will require substantial additional financing to achieve our goals, and a failure to obtain this capital when needed or on acceptable terms could force us to delay, limit, reduce or terminate our development and commercialization efforts.

Since our inception, significant portions of our resources have been dedicated to research and development, as well as demonstrating the effectiveness of our technology, including through the retrofit of the Agri-Energy Facility. We believe that we will continue to expend substantial resources for the foreseeable future on further developing our technologies, developing future markets for our isobutanol and accessing and Retrofitting facilities necessary for the production of isobutanol on a commercial scale. These expenditures will include costs associated with research and development, accessing existing ethanol plants, Retrofitting or otherwise modifying the plants (including the Redfield Facility (as defined below)) to produce isobutanol, obtaining government and regulatory approvals, acquiring or constructing storage facilities and negotiating supply agreements for the isobutanol we produce. In addition, other unanticipated costs may arise. Because the costs of developing our technology at a commercial scale are highly uncertain, we cannot reasonably estimate the amounts necessary to successfully commercialize our production.

To date, we have funded our operations primarily through equity offerings, issuances of debt, borrowing under our secured debt financing arrangements and revenues earned primarily from the sale of ethanol. Based on our current plans and expectations, we will require additional funding to achieve our goals. In addition, the cost of preparing, filing, prosecuting, maintaining and enforcing patent, trademark and other intellectual property rights and defending against claims by others that we may be violating their intellectual property rights, including the current litigation with Butamax, will be significant. Moreover, our plans and expectations may change as a result of factors currently unknown to us, and we may need additional funds sooner than planned and may seek to raise additional funds through public or private debt or equity financings in the near future. We may also choose to seek additional capital sooner than required due to favorable market conditions or strategic considerations.

Our future capital requirements will depend on many factors, including:

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the timing of, and costs involved in developing and optimizing our technologies for full-scale commercial production of isobutanol;

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the timing of, and costs involved in accessing existing ethanol plants;

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the timing of, and costs involved in Retrofitting the plants we access with our technologies;

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the costs involved in establishing enhanced yeast seed trains;

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the costs involved in acquiring and deploying additional equipment to attain final product specifications that may be required by future customers;

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the cost of operating, maintaining and increasing production capacity of the Retrofitted plants;

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our ability to negotiate agreements supplying suitable biomass to our plants, and the timing and terms of those agreements;

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the timing of, and the costs involved in developing adequate storage facilities for the isobutanol we produce;

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our ability to gain market acceptance for isobutanol as a specialty chemical, gasoline blendstock and as a raw material for the production of hydrocarbons;

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our ability to negotiate supply agreements for the isobutanol we produce, and the timing and terms of those agreements, including terms related to sales price;

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our ability to negotiate sales of our isobutanol for full-scale production of butenes and other industrially useful chemicals and fuels, and the timing and terms of those sales, including terms related to sales price;

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our ability to sell the iDGs™ left as a co-product of fermenting isobutanol from corn as animal feedstock;

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our ability to establish and maintain strategic partnerships, licensing or other arrangements and the timing and terms of those arrangements; and

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the cost of preparing, filing, prosecuting, maintaining, defending and enforcing patent, trademark and other intellectual property claims, including litigation costs and the outcome of such litigation.

Additional funds may not be available when we need them, on terms that are acceptable to us, or at all. In addition, our ability to raise additional funds will be subject to certain limitations in the indenture governing the 2013 Notes and the agreements governing our secured indebtedness with TriplePoint. If needed funds are not available to us on a timely basis, we may be required to delay, limit, reduce or terminate:

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our research and development activities;

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our plans to access and/or Retrofit existing ethanol facilities;

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our production of isobutanol at Retrofitted plants; and/or

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our activities in developing storage capacity and negotiating supply agreements that may be necessary for the commercialization of our isobutanol production.

Our retrofit of the Agri-Energy Facility is our first commercial retrofit and, as a result, our full-scale commercial production of isobutanol at the Agri-Energy Facility could be delayed or we could experience significant cost overruns in comparison to our current estimates.

In September 2010, we acquired ownership of the Agri-Energy Facility in Luverne, Minnesota. We have substantially completed the retrofit of the Agri-Energy Facility and in June 2013, we resumed the limited production of isobutanol at the Agri-Energy Facility operating one fermenter and one GIFT^® separation system in single production train mode using a dextrose (sugar) feedstock. In August 2013, we expanded production at the Agri-Energy Facility to dual production train mode by adding a second fermenter and second GIFT^® system. Based on the results of these initial production runs, in October 2013 we commissioned the Agri-Energy Facility on corn mash for fully integrated production. We plan to continue producing isobutanol throughout the remainder of 2013 with the objective of testing production run rates

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and then further ramping up production toward nameplate capacity in 2014. Cost overruns or other unexpected difficulties related to transitioning to sugars obtained from corn mash, increasing production levels at this facility to nameplate capacity and achieving our target customers’ product specifications could cause the final retrofit to take longer or cost more than we anticipate which could further increase our need for funding. For instance, we intend to acquire and install a product purification column as a finishing step in the production of our isobutanol at the Agri-Energy Facility which we believe will allow us to achieve our target customers’ product specifications without continuing to rely on third-party contract tolling providers. Such funds may not be available when we need them, on terms that are acceptable to us or at all. In addition, our ability to raise additional funds will be subject to certain limitations in the indenture governing the 2013 Notes and the agreements governing our secured indebtedness with TriplePoint. If additional funding is not available to us, or not available on terms acceptable to us, our ability to optimize the isobutanol production technology currently in place at the Agri-Energy Facility and achieve full-scale commercial production at this facility may be limited. Such a result could reduce the scope of our business plan and have an adverse effect on our results of operations.

We have entered into a joint venture with Redfield Energy, LLC to Retrofit the Redfield Facility, and our production of isobutanol at the Redfield Facility could be delayed or we could experience significant cost overruns in comparison to our current estimates.

In June 2011, we acquired access to a 50 MGPY ethanol production facility located near Redfield, South Dakota (the “Redfield Facility”), pursuant to our joint venture with Redfield Energy, LLC, a South Dakota limited liability company (“Redfield”). We intend to Retrofit this facility to produce isobutanol, and will need access to additional capital in order to commence the Retrofit. Although we will be able to apply our experience from the retrofit of the Agri-Energy Facility, no two ethanol facilities are exactly alike, and each Retrofit will require individualized engineering and design work. Cost overruns or other unexpected difficulties unique to the Redfield Facility could cause the Retrofit to cost more than we anticipate which could further increase our need for funding. Such funds may not be available when we need them, on terms that are acceptable to us or at all, which could delay our full-scale commercial production of isobutanol at this facility. In addition, our ability to raise additional funds will be subject to certain limitations in the indenture governing the 2013 Notes and the agreements governing our secured indebtedness with TriplePoint. If additional funding is not available to us, or not available on terms acceptable to us, our ability to complete the Retrofit of the Redfield Facility, which is not yet underway, or acquire access to or Retrofit additional ethanol plants may be limited. Such a result could reduce the scope of our business plan and have an adverse effect on our results of operations.

Our ability to compete may be adversely affected if we are unsuccessful in defending against any claims by competitors or others that we are infringing upon their intellectual property rights, such as if Butamax is successful in its lawsuits alleging that we are infringing its patents for the production of isobutanol using certain microbial host cells.

The various bioindustrial markets in which we plan to operate are subject to frequent and extensive litigation regarding patents and other intellectual property rights. In addition, many companies in intellectual property-dependent industries, including the renewable energy industry, have employed intellectual property litigation as a means to gain an advantage over their competitors. As a result, we may be required to defend against claims of intellectual property infringement that may be asserted by our competitors against us and, if the outcome of any such litigation is adverse to us, it may affect our ability to compete effectively. Currently, we are defending ourselves against lawsuits filed by Butamax alleging that we have infringed eight patents, including five patents covering certain recombinant microbial host cells that produce isobutanol and methods for the production of isobutanol using such host cells, a patent covering a modified Pseudomonas KARI enzyme, a patent covering a modified E. coli KARI enzyme, and a patent covering the use of L. lactis and S. mutans dihydroxy acid dehydratase enzymes in yeast. The litigation with Butamax is dynamic. We have filed complaints alleging infringement of certain of our patents by Butamax and we anticipate that additional patents involving

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the isobutanol production process that are issued to Butamax, its members or us will be involved in litigation. The next District Court trial for the Butamax litigation is scheduled for July 2014 and additional trials are currently scheduled for August 2015. Also, on April 19, 2013 Butamax filed a notice of appeal to the U.S. Court of Appeals for the Federal Circuit to appeal the District Court of Delaware’s Memorandum and Order of March 19, 2013, and the District Court of Delaware’s Amended Final Judgment of April 10, 2013, relating to Case No. 1:11-cv-00054-SLR. In that case, Butamax alleged that we were infringing one or more claims of U.S. Patent Nos. 7,851,188 and 7,993,889. Following the court’s construction of a key term in the patents and its ruling of no infringement under the doctrine of equivalents, Butamax stipulated to no literal infringement under the court’s construction and the court entered judgment. The hearing for Butamax’s appeal to the U.S. Court of Appeals for the Federal Circuit was held on November 7, 2013.

Our involvement in litigation, interferences, opposition proceedings or other intellectual property proceedings inside and outside of the U.S. may divert management time from focusing on business operations, could cause us to spend significant amounts of money and may have no guarantee of success. Any current and future intellectual property litigation could also force us to do one or more of the following:

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stop selling, incorporating, manufacturing or using our products that use the subject intellectual property;

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obtain from a third party asserting its intellectual property rights, a license to sell or use the relevant technology, which license may not be available on reasonable terms, or at all;

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redesign those products or processes, such as our process for producing isobutanol, that use any allegedly infringing or misappropriated technology, which may result in significant cost or delay to us, or which redesign could be technically infeasible;

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pay attorneys’ fees and expenses; or

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pay damages, including the possibility of treble damages in a patent case if a court finds us to have willfully infringed certain intellectual property rights.

We are aware of a significant number of patents and patent applications relating to aspects of our technologies filed by, and issued to, third parties, including, but not limited to Butamax. We cannot assure you that we will ultimately prevail if any of this third-party intellectual property is asserted against us or that we will ultimately prevail in the patent infringement litigation with Butamax.

The Agri-Energy Facility is our first commercial isobutanol production facility, and, as such, we may be unable to produce planned quantities of isobutanol and any such production may be more costly than we anticipate.

In May 2012, we announced that we had commenced initial start-up operations for the retrofit of the Agri-Energy Facility to isobutanol production. In September 2012, as a result of a lower than planned production rate of isobutanol and some microbial contamination in our plant, we made the strategic decision to pause isobutanol production at the Agri-Energy Facility for a period of time to focus on optimizing specific parts of our technology to further enhance isobutanol production rates as well as controlling and managing contamination. During the period from November 2012 to June 2013, we developed and implemented changes that we believe will allow us to manage the contamination issues that significantly contributed to the lower than planned isobutanol production rates observed in the initial startup production period by changing the fermentation conditions and related operating parameters, making equipment modifications to improve sterility, and, most importantly, improving the operating procedures we use at the plant. As of result of these efforts, in June 2013 we resumed the limited production of isobutanol operating one fermenter and one GIFT^® separation system in single production train mode using a dextrose (sugar) feedstock. In August 2013, we expanded production at the Agri-Energy Facility to dual production train mode by adding a second

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fermenter and second GIFT^® system. Based on the results of these initial production runs, in October 2013 we commissioned the Agri-Energy Facility on corn mash for fully integrated production. We plan to continue producing isobutanol throughout the remainder of 2013 with the objective of testing production run rates and then further ramping up production toward nameplate capacity in 2014. We may encounter further production challenges, including, but not limited to, being unable to manage plant contamination, and we may need to add additional processing steps or incur additional capital expenditures to achieve our target customers’ product specifications. Any such production challenges may delay our ramp up of production capacity, prevent us from producing significant quantities of isobutanol or significantly increase our cost to produce isobutanol, which could have a material adverse effect on our business, financial condition and results of operations.

Some of our Retrofits, including the retrofit of the Agri-Energy Facility, will include additional equipment that we believe will allow us to switch between ethanol and isobutanol production but we cannot guarantee that we will be successful in switching between isobutanol and ethanol production in a timely or efficient manner at these facilities.

While we have designed the retrofit of the Agri-Energy Facility to allow the capability to switch between isobutanol and ethanol production, which may, subject to regulatory factors and depending on market conditions, mitigate certain significant risks associated with start-up operations for isobutanol production, there can be no assurance that we will be able to revert to ethanol production or that it will make sense, based on the then-current economic conditions for the production of ethanol, to do so. Even if we are able to revert to ethanol production, the facility may produce ethanol less efficiently or in lower volumes than it did prior to the Retrofit and such ethanol production may not generate positive economic returns. If we are unable to produce isobutanol at the volumes, rates and costs that we expect and are unable to revert to ethanol production at full capacity, we would be unable to match the facility’s historical economic performance and our business, financial condition and results of operations would be materially adversely affected.

We may not be successful in the development of individual steps in, or an integrated process for, the production of commercial quantities of isobutanol from plant feedstocks in a timely or economic manner, or at all.

As of the date of this prospectus supplement, we have produced only limited quantities of isobutanol at commercial scale and we may not be successful in increasing our production from these limited startup production levels to nameplate production levels. The production of isobutanol requires multiple integrated steps, including:

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obtaining the plant feedstocks;

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treatment with enzymes to produce fermentable sugars;

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fermentation by organisms to produce isobutanol from the fermentable sugars;

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distillation of the isobutanol to concentrate and separate it from other materials;

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purification of the isobutanol; and

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storage and distribution of the isobutanol.

Our future success depends on our ability to produce commercial quantities of isobutanol in a timely and economic manner. Our biocatalysts have not yet produced commercial volumes of isobutanol at nameplate production levels. While we have produced isobutanol using our biocatalysts at our laboratories in Colorado, at the one MGPY demonstration facility and at the Agri-Energy Facility, such production was not at full nameplate capacity. Our 2013 startup runs were focused on producing isobutanol from dextrose (sugar) and challenges remain in achieving substantial production volumes with other sugars, including sugars obtained from corn mash. The risk of contamination and other problems

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rise as we increase the scale of our isobutanol production. If we are unable to successfully manage these risks, we may encounter difficulties in achieving our target isobutanol production yield, rate, concentration or purity at a commercial scale, which could delay or increase the costs involved in commercializing our isobutanol production. In addition, we have limited experience sourcing large quantities of feedstocks and in storing and/or distributing significant volumes of isobutanol. The technological and logistical challenges associated with each of the processes involved in production, sale and distribution of isobutanol are extraordinary, and we may not be able to resolve any difficulties that arise in a timely or cost effective manner, or at all. Even if we are successful in developing an economical process for converting plant feedstocks into commercial quantities of isobutanol, we may not be able to adapt such process to other biomass raw materials, including cellulosic biomass.

Prior to commencement of the Agri-Energy Facility retrofit, neither we nor ICM had ever built (through Retrofit or otherwise) or operated a commercial isobutanol facility. We assume that we understand how the engineering and process characteristics of the one MGPY demonstration facility will scale up to larger facilities, but these assumptions may prove to be incorrect. Accordingly, we cannot be certain that we can consistently produce isobutanol in an economical manner in commercial quantities. If our costs to build large-scale commercial isobutanol facilities are significantly higher than we expect or if we fail to consistently produce isobutanol economically on a commercial scale or in commercial volumes, our commercialization of isobutanol and our business, financial condition and results of operations will be materially adversely affected.

We may not be able to successfully identify and acquire access to additional ethanol production facilities suitable for efficient Retrofitting, or acquire access to sufficient capacity to be commercially viable or meet customer demand.

Our strategy currently includes accessing and Retrofitting, either independently or with potential development partners or licensees, existing ethanol facilities for the production of large quantities of isobutanol for commercial distribution and sale. In addition to the Agri-Energy Facility, we have acquired access to the 50 MGPY Redfield Facility pursuant to our joint venture with Redfield. However, we may not find future development partners with whom we can implement this growth strategy, and we may not be able to identify facilities suitable for joint venture, acquisition, lease or license.

Even if we successfully identify a facility suitable for efficient Retrofitting, we may not be able to acquire access to such facility in a timely manner, if at all. The owners of the ethanol facility may reach an agreement with another party, refuse to consider a joint venture, acquisition, lease or license, or demand more or different consideration than we are willing to provide. In particular, if the profitability of ethanol production increases, plant owners may be less likely to consider modifying their production, and thus may be less willing to negotiate with us or agree to allow us to Retrofit their facilities for isobutanol production. We may also find that it is necessary to offer special terms, incentives and/or rebates to owners of ethanol facilities that allow us to access and Retrofit their facilities while our production technology is being proven on a commercial scale. Even if the owners of a facility are interested in reaching an agreement that grants us access to the plant, negotiations may take longer or cost more than we expect, and we may never achieve a final agreement. Further, our ability to raise additional funds will be subject to certain limitations in the indenture governing the 2013 Notes and the agreements governing our secured indebtedness with TriplePoint and we may not be able to raise capital on acceptable terms, or at all, to finance our joint venture, acquisition, participation or lease of facilities.

Even if we are able to access and Retrofit several facilities, we may fail to access enough capacity to be commercially viable or meet the volume demands or minimum requirements of our customers, including pursuant to definitive supply or distribution agreements that we may enter into, which may subject us to monetary damages. For example, under the terms of our international off-take and distribution agreement with Sasol, we are required to pay certain shortfall fees if we are not able to supply Sasol with

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certain minimum quantities of product. We may also be required to repay funds received from Toray Industries if we are not able to produce and deliver a minimum quantity of bio-PX by April 30, 2014. Failure to acquire access to sufficient capacity in a timely manner and on favorable terms may slow or stop our commercialization process, which could have a material adverse effect on our business, financial condition and results of operations.

Once we acquire access to ethanol facilities, we may be unable to successfully Retrofit them to produce isobutanol, or we may not be able to Retrofit them in a timely and cost-effective manner.

For each ethanol production facility to which we acquire access, we will be required to obtain numerous regulatory approvals and permits to Retrofit and operate the facility. In the U.S., these include such items as a modification to the air permit, fuel registration with the EPA, ethanol excise tax registration and others. These requirements may not be satisfied in a timely manner, or at all. Later-enacted federal and state governmental requirements may also substantially increase our costs or delay or prevent the completion of a Retrofit, which could have a material adverse effect on our business, financial condition and results of operations.

No two ethanol facilities are exactly alike, and each Retrofit will require individualized engineering and design work. There is no guarantee that we or any contractor we retain will be able to successfully design a commercially viable Retrofit, or properly complete the Retrofit once the engineering plans are completed. Prior to commencement of the Agri-Energy Facility retrofit, neither we nor ICM had ever built, via Retrofit or otherwise, a full-scale commercial isobutanol facility. Despite our experience with the retrofit of the Agri-Energy Facility, our estimates of the capital costs that we will need to incur to Retrofit a commercial-scale ethanol facility may prove to be inaccurate, and each Retrofit may cost materially more to engineer and build than we currently anticipate. For example, our estimates assume that each plant we Retrofit will be performing at full production capacity, and we may need to expend substantial sums to repair or modify underperforming facilities prior to Retrofit.

Our Retrofit design to convert existing ethanol production capacity to isobutanol production capacity was developed in cooperation with ICM and is based on ICM technology. There is no guarantee that this Retrofit design will be compatible with existing ethanol facilities that do not utilize ICM technology. Before we can Retrofit such facilities, we may need to modify them to be compatible with our Retrofit design. This may require significant additional expenditure of time and money, and there is no guarantee such modification will be successful.

Furthermore, the Retrofit of acquired facilities will be subject to the risks inherent in the build-out of any manufacturing facility, including risks of delays and cost overruns as a result of factors that may be out of our control, such as delays in the delivery of equipment and subsystems or the failure of such equipment to perform as expected once delivered. In addition, we will depend on third-party relationships in expanding our isobutanol production capacity and such third parties may not fulfill their obligations to us under our arrangements with them. Delays, cost overruns or failures in the Retrofit process will slow our commercial production of isobutanol and harm our performance.

Though our retrofit design for the Agri-Energy Facility includes the capability to switch between isobutanol and ethanol production, we may be unable to successfully revert to ethanol production, or the facility may produce ethanol less efficiently or in lower volumes than it did before the Retrofit. In addition, we may be unable to secure the necessary regulatory approvals and permits to switch between isobutanol and ethanol production in a timely manner, or at all. Thus, if we fail to achieve commercial levels of isobutanol production at a Retrofitted facility, we may be unable to rely on ethanol production as an alternative revenue source, which could have a material adverse effect on our prospects.

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Our facilities and process may fail to produce isobutanol at the volumes, rates and costs we expect.

Some or all of the facilities we choose to Retrofit may be in locations distant from corn or other feedstock sources, which could increase our feedstock costs or prevent us from acquiring sufficient feedstock volumes for commercial production. General market conditions might also cause increases in feedstock prices, which could likewise increase our production costs.

Even if we secure access to sufficient volumes of feedstock, the facilities we Retrofit for isobutanol production may fail to perform as expected. The equipment and subsystems installed during the Retrofit may never operate as planned. Our systems may prove incompatible with the original facility, or require additional modification after installation. Our biocatalyst may perform less efficiently than it did in testing, if at all. Contamination of plant equipment may require us to replace our biocatalyst more often than expected, require unplanned installation or replacement of equipment, or cause our fermentation process to yield undesired or harmful by-products. Likewise, our feedstock may contain contaminants like wild yeast, which naturally ferments feedstock into ethanol. The presence of contaminants, such as wild yeast, in our feedstock could reduce the purity of the isobutanol that we produce and require us to invest in more costly isobutanol separation processes or equipment. Unexpected problems may force us to cease or delay production and the time and costs involved with such delays may prove prohibitive. Any or all of these risks could prevent us from achieving the production throughput and yields necessary to achieve our target annualized production run rates and/or to meet the volume demands or minimum requirements of our customers, including pursuant to definitive supply or distribution agreements that we may enter into, which may subject us to monetary damages. For example, under the terms of our international off-take and distribution agreement with Sasol, we are required to pay certain shortfall fees if we are not able to supply Sasol with certain minimum quantities of product. We may also be required to repay funds received from Toray Industries if we are not able to produce and deliver a minimum quantity of bio-PX by April 30, 2014. Failure to achieve these rates or meet these minimum requirements, or achieving them only after significant additional expenditures, could substantially harm our commercial performance.

We may be unable to produce isobutanol in accordance with customer specifications.

Even if we produce isobutanol at our targeted rates, we may be unable to produce isobutanol that meets customer specifications. We may need to add additional processing steps or incur capital expenditures in order to meet customer specifications which could add significant costs to our production process. For example, at the Agri-Energy Facility we intend to acquire and install a product purification column, which we believe will allow us to achieve our target customers’ product specifications without continuing to rely on third-party contract tolling providers. If we fail to meet specific product or volume specifications contained in a supply agreement, the customer may have the right to seek an alternate supply of isobutanol and/or terminate the agreement completely, and we could be required to pay shortfall fees or otherwise be subject to damages. For example, under the terms of our international off-take and distribution agreement with Sasol, we are required to meet defined high-purity isobutanol product standards. A failure to successfully meet the specifications of our potential customers could decrease demand, and significantly hinder market adoption of our products.

We lack significant experience operating commercial-scale ethanol and isobutanol facilities, and may encounter substantial difficulties operating commercial plants or expanding our business.

We have very limited experience operating commercial-scale ethanol and isobutanol facilities. Accordingly, we may encounter significant difficulties operating at a commercial scale. We believe that our future facilities will, like the Agri-Energy Facility, be able to continue producing ethanol during much of the Retrofit process. We will need to successfully administer and manage this production. Though ICM and the employees of Agri-Energy and Redfield are experienced in the operation of ethanol facilities, and our future development partners or the entities that we acquire may likewise have such

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experience, we may be unable to manage ethanol-producing operations, especially given the possible complications associated with a simultaneous Retrofit. Once we complete a commercial Retrofit, operational difficulties may increase, because neither we nor anyone else has significant experience operating a pure isobutanol fermentation facility at a commercial scale. The skills and knowledge gained in operating commercial ethanol facilities or small-scale isobutanol plants may prove insufficient for successful operation of a large-scale isobutanol facility, and we may be required to expend significant time and money to develop our capabilities in isobutanol facility operation. We may also need to hire new employees or contract with third parties to help manage our operations, and our performance will suffer if we are unable to hire qualified parties or if they perform poorly.

We may face additional operational difficulties as we further expand our production capacity. Integrating new facilities with our existing operations may prove difficult. Rapid growth, resulting from our operation of, or other involvement with, isobutanol facilities or otherwise, may impose a significant burden on our administrative and operational resources. To effectively manage our growth and execute our expansion plans, we will need to expand our administrative and operational resources substantially and attract, train, manage and retain qualified management, technicians and other personnel. We may be unable to do so. Failure to meet the operational challenges of developing and managing increased isobutanol production, or failure to otherwise manage our growth, may have a material adverse effect on our business, financial condition and results of operations.

We may have difficulty adapting our technology to commercial-scale fermentation, which could delay or prevent our commercialization of isobutanol.

While we have demonstrated the ability to produce isobutanol under the demonstration plant operating conditions and under commercial scale operating conditions at the Agri-Energy Facility, and we have succeeded in reaching our commercial fermentation performance targets for isobutanol concentration, fermentation productivity and isobutanol yield in laboratory tests, we have not yet accomplished these performance targets in a commercial plant environment. Our efforts to address lower than expected production rates at the Agri-Energy Facility during our initial startup operations resulted in our decision to temporarily pause isobutanol production at the facility in September 2012.

In June 2013, we resumed the limited production of isobutanol operating one fermenter and one GIFT^® separation system in single production train mode at the Agri-Energy Facility using a dextrose (sugar) feedstock. In August 2013, we expanded production at the Agri-Energy Facility to dual production train mode by adding a second fermenter and second GIFT^® system. Based on the results of these initial production runs, in October 2013 we commissioned the Agri-Energy Facility on corn mash for fully integrated production. We plan to continue producing isobutanol throughout the remainder of 2013 with the objective of testing production run rates and then further ramping up production toward nameplate capacity in 2014. The process of increasing production to nameplate production levels using sugars obtained from corn mash, if it succeeds, may take longer or cost more than expected.

Our yeast biocatalyst may not be able to meet the commercial performance targets at nameplate production capacity using sugars obtained from corn mash in a timely manner, or ever. In addition, the risk of contamination and other problems may increase as we seek to ramp up our production capacity, which could negatively impact our cost of production. If we encounter difficulties in optimizing our production, our commercialization of isobutanol and our business, financial condition and results of operations will be materially adversely affected.

We may have difficulties gaining market acceptance and successfully marketing our isobutanol to customers, including chemical producers, fuel distributors and refiners.

A key component of our business strategy is to market our isobutanol to chemical producers, fuels distributors and refiners. We have no experience marketing isobutanol on a commercial scale and we

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may fail to successfully negotiate marketing agreements in a timely manner or on favorable terms. If we fail to successfully market our isobutanol to refiners, fuels distributors and chemical producers, our business, financial condition and results of operations will be materially adversely affected.

We also intend to market our isobutanol to chemical producers for use in making various chemicals such as isobutylene, a type of butene that can be produced through the dehydration of isobutanol. Although a significant market currently exists for isobutylene produced from petroleum, which is widely used in the production of plastics, specialty chemicals, alkylate for gasoline blending and high octane aviation gasoline, no one has successfully created isobutylene on a commercial scale from bio-isobutanol. Therefore, to gain market acceptance and successfully market our isobutanol to chemical producers, we must show that our isobutanol can be converted into isobutylene at a commercial scale. As no company currently dehydrates commercial volumes of isobutanol into isobutylene, we must demonstrate the large-scale feasibility of the process and reach agreements with companies that are willing to invest in the necessary dehydration infrastructure. Failure to reach favorable agreements with these companies, or the inability of their plants to convert isobutanol into isobutylene at sufficient scale, will slow our development in the chemicals market and could significantly affect our profitability.

Obtaining market acceptance in the chemicals industry is complicated by the fact that many potential chemicals industry customers have invested substantial amounts of time and money in developing petroleum-based production channels. These potential customers generally have well-developed manufacturing processes and arrangements with suppliers of chemical components, and may display substantial resistance to changing these processes. Pre-existing contractual commitments, unwillingness to invest in new infrastructure, distrust of new production methods and lengthy relationships with current suppliers may all slow market acceptance of isobutanol.

No market currently exists for isobutanol as a fuel or as a gasoline blendstock. Therefore, to gain market acceptance and successfully market our isobutanol to fuels distributors and refiners, we must effectively demonstrate the commercial advantages of using isobutanol over other biofuels and blendstocks, as well as our ability to produce isobutanol reliably on a commercial scale at a sufficiently low cost. We must show that isobutanol is compatible with existing infrastructure and does not damage pipes, engines, storage facilities or pumps. We must also overcome marketing and lobbying efforts by producers of other biofuels and blendstocks, including ethanol, many of whom may have greater resources than we do. If the markets for isobutanol as a fuel or as a gasoline blendstock do not develop as we currently anticipate, or if we are unable to penetrate these markets successfully, our revenue and revenue growth rate, if any, could be materially and adversely affected.

We believe that consumer demand for environmentally sensitive products will drive demand among large brand owners for renewable hydrocarbon sources. One of our marketing strategies is to leverage this demand to obtain commitments from large brand owners to purchase products made from our isobutanol by third parties. We believe these commitments will, in turn, promote chemicals industry demand for our isobutanol. If consumer demand for environmentally sensitive products fails to develop at sufficient scale or if such demand fails to drive large brand owners to seek sources of renewable hydrocarbons, our revenue and growth rate could be materially and adversely affected.

We may face substantial delay in getting regulatory approvals for use of our isobutanol in the fuels and chemicals markets, which could substantially hinder our ability to commercialize our products.

Large-scale commercialization of our isobutanol may require approvals from state and federal agencies. Before we can sell isobutanol as a fuel or as a gasoline blendstock directly to large petroleum refiners, we must receive EPA fuel certification. We have filed EPA Part 79 registration to move our small business registration to a full registration (including Tier 1 EPA testing), and the approval process may require significant time. Approval can be delayed for years, and there is no guarantee of receiving it.

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Additionally, California requires that fuels meet both its fuel certification requirements and a separate state low-carbon fuel standard. Any delay in receiving approval will slow or prevent the commercialization of our isobutanol for fuel markets, which could have a material adverse effect on our business, financial condition and results of operations.

With respect to the chemicals markets, we plan to focus on isobutanol production and sell to companies that can convert our isobutanol into other chemicals, such as isobutylene. However, should we later decide to produce these other chemicals ourselves, we may face similar requirements for EPA and other regulatory approvals. Approval, if ever granted, could be delayed for substantial amounts of time, which could significantly harm the development of our business and prevent the achievement of our goals.

Our isobutanol fermentation process utilizes a genetically modified organism which, when used in an industrial process, is considered a new chemical under the EPA’s Toxic Substances Control Act (“TSCA”). The TSCA requires us to comply with the EPA’s Microbial Commercial Activity Notice process to operate plants producing isobutanol using our biocatalysts. The TSCA’s new chemicals submission policies may change and additional government regulations may be enacted that could prevent or delay regulatory approval of our isobutanol production.

There are various third-party certification organizations, such as ASTM and Underwriters’ Laboratories, Inc., involved in standard-setting regarding the transportation, dispensing and use of liquid fuel in the U.S. and abroad. These organizations may change the current standards and additional requirements may be enacted that could prevent or delay approval of our products. The process of seeking required approvals and the continuing need for compliance with applicable standards may require the expenditure of substantial resources, and there is no guarantee that we will satisfy these standards in a timely manner, if ever.

In addition, to Retrofit or otherwise modify ethanol facilities and operate the Retrofitted and modified plants to produce isobutanol, we will need to obtain and comply with a number of permit requirements. As a condition to granting necessary permits, regulators may make demands that could increase our Retrofit, modification or operations costs, and permit conditions could also restrict or limit the extent of our operations, which could delay or prevent our commercial production of isobutanol. We cannot guarantee that we will be able to meet all regulatory requirements or obtain and comply with all necessary permits to complete our planned ethanol plant Retrofits, and failure to satisfy these requirements in a timely manner, or at all, could have a substantial negative effect on our performance.

Jet fuels must meet various statutory and regulatory requirements before they may be used in commercial aviation. In the U.S., the use of specific jet fuels is regulated by the Federal Aviation Administration (“FAA”). Rather than directly approving specific fuels, the FAA certifies individual aircraft for flight. This certification includes authorization for an aircraft to use the types of fuels specified in its flight manual. To be included in an aircraft’s flight manual, the fuel must meet standards set by ASTM. The current ASTM requirements do not permit the use of jet fuel derived from isobutanol, and we will need to give ASTM sufficient data to justify creating a new standard applicable to ATJ. Though our work testing isobutanol-based ATJ with the U.S. Air Force Research Laboratory has provided us with data we believe ASTM will take into consideration, the process of seeking required approvals and the continuing need for compliance with applicable statutes and regulations will require the expenditure of substantial resources. Failure to obtain regulatory approval in a timely manner, or at all, could have a significant negative effect on our operations.

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We may be unable to successfully negotiate final, binding terms related to our current non-binding isobutanol supply and distribution agreements, which could harm our commercial prospects.

In addition to a limited number of definitive supply and distribution agreements, we have agreed to preliminary terms regarding supplying isobutanol or the products derived from it to various companies for their use or further distribution, including LANXESS, United Airlines, and TOTAL PETROCHEMICALS USA, Inc. We may be unable to negotiate final terms with these or other companies in a timely manner, or at all, and there is no guarantee that the terms of any final agreement will be the same or similar to those currently contemplated in our preliminary agreements. Final terms may include less favorable pricing structures or volume commitments, more expensive delivery or purity requirements, reduced contract durations and other adverse changes. Delays in negotiating final contracts could slow our initial isobutanol commercialization, and failure to agree to definitive terms for sales of sufficient volumes of isobutanol could prevent us from growing our business. To the extent that terms in our initial supply and distribution contracts may influence negotiations regarding future contracts, the failure to negotiate favorable final terms related to our current preliminary agreements could have an especially negative impact on our growth and profitability. Additionally, as we have yet to produce or supply commercial volumes of isobutanol to any customer, we have not demonstrated that we can meet the production levels contemplated in our current non-binding supply agreements. If our production scale-up proceeds more slowly than we expect, or if we encounter difficulties in successfully completing plant Retrofits, potential customers, including those with whom we have current letters of intent, may be less willing to negotiate definitive supply agreements, or demand terms less favorable to us, and our performance may suffer.

Even if we are successful in consistently producing isobutanol on a commercial scale, we may not be successful in negotiating sufficient supply agreements for our production.

We expect that many of our customers will be large companies with extensive experience operating in the fuels or chemicals markets. As a development stage company, we lack commercial operating experience, and may face difficulties in developing marketing expertise in these fields. Our business model relies upon our ability to successfully negotiate and structure long-term supply agreements for the isobutanol we produce. Many of our potential customers may be more experienced in these matters than we are, and we may fail to successfully negotiate these agreements in a timely manner or on favorable terms which, in turn, may force us to slow our production, delay our acquiring and Retrofitting of additional plants, dedicate additional resources to increasing our storage capacity and/or dedicate resources to sales in spot markets. Furthermore, should we become more dependent on spot market sales, our profitability will become increasingly vulnerable to short-term fluctuations in the price and demand for petroleum-based fuels and competing substitutes.

Even if we are successful in consistently producing isobutanol on a commercial scale, we may not be successful in negotiating pricing terms sufficient to generate positive results from operations at the Agri-Energy Facility.

We expect that many of our customers will be large companies with extensive experience operating in the fuels or chemicals markets. As a development stage company, we lack commercial operating experience, and may face difficulties in developing marketing expertise in these fields. Our business model relies upon our ability to negotiate pricing terms for the isobutanol we produce that generate positive results from the operations of the Agri-Energy Facility. Many of our potential customers may be more experienced in these matters than we are. We may fail to negotiate these agreements in a timely manner, which may force us to dedicate resources to sales in spot markets. If we become more dependent on spot market sales our profitability will become increasingly vulnerable to short-term fluctuations in the price and demand for our products.

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Our isobutanol may encounter physical or regulatory issues, which could limit its usefulness as a gasoline blendstock.

In the gasoline blendstock market, isobutanol can be used in conjunction with, or as a substitute for, ethanol and other widely used fuel oxygenates, and we believe our isobutanol will be physically compatible with typical gasoline engines. However, there is a risk that under actual engine conditions, isobutanol will face significant limitations, making it unsuitable for use in high percentage gasoline blends. Additionally, current regulations limit gasoline blends to low percentages of isobutanol, and also limit combination isobutanol-ethanol blends. Government agencies may maintain or even increase the restrictions on isobutanol gasoline blends. As we believe that the potential to use isobutanol in higher percentage blends than is feasible for ethanol will be an important factor in successfully marketing isobutanol to refiners, a low blend wall could significantly limit commercialization of isobutanol as a gasoline blendstock.

Our isobutanol may be less compatible with existing refining and transportation infrastructure than we believe, which may hinder our ability to market our product on a large scale.

We developed our business model based on our belief that our isobutanol is fully compatible with existing refinery infrastructure. For example, when making isobutanol blends, we believe that gasoline refineries will be able to pump our isobutanol through their pipes and blend it in their existing facilities without damaging their equipment. If our isobutanol proves unsuitable for such handling, it will be more expensive for refiners to use our isobutanol than we anticipate, and they may be less willing to adopt it as a gasoline blendstock, forcing us to seek alternative purchasers.

Likewise, our plans for marketing our isobutanol are based upon our belief that it will be compatible with the pipes, tanks and other infrastructure currently used for transporting, storing and distributing gasoline. If our isobutanol or products incorporating our isobutanol cannot be transported with this equipment, we will be forced to seek alternative transportation arrangements, which will make our isobutanol and products produced from our isobutanol more expensive to transport and less appealing to potential customers. Reduced compatibility with either refinery or transportation infrastructure may slow or prevent market adoption of our isobutanol, which could substantially harm our performance.

We may be required to obtain additional regulatory approvals for use of our iDGs™ as animal feed, which could delay our ability to sell iDGs™ increasing our net cost of production and harming our operating results.

Most of the ethanol plants we initially plan to Retrofit use dry-milled corn as a feedstock. Once we have optimized our full-scale commercial isobutanol production process, we plan to sell, as animal feed, the iDGs™ left as a co-product of fermenting isobutanol from dry-milled corn. We believe that this will enable us to offset a significant portion of the expense of purchasing corn for fermentation. We are currently approved to sell iDGs™ as animal feed through a self-assessed Generally Regarded as Safe (GRAS) process via third party scientific review. In order to improve the value of our iDGs™, we are also in the process of obtaining U.S. Food and Drug Administration (“FDA”) approval for the marketing of our iDGs™. We believe obtaining FDA approval will increase the value of our iDGs™ by offering customers of our iDGs™ further assurance of the safety of our iDGs™. If we make changes in our biocatalyst whereby we can no longer rely on our GRAS process, we would be required to obtain FDA approval for marketing our iDGs™. FDA testing and approval can take a significant amount of time, and there is no guarantee that we will ever receive such approval. If FDA approval is delayed or never obtained, or if we are unable to secure market acceptance for our iDGs™, our net cost of production will increase, which may hurt our operating results.

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Our development strategy relies heavily on our relationship with ICM.

We rely heavily upon our relationship with ICM. In October 2008, we entered into a development agreement and a commercialization agreement with ICM, each of which has since been amended. Pursuant to the terms of the development agreement, ICM engineers helped us install the equipment necessary to test and develop our isobutanol fermentation process at ICM’s one MGPY ethanol demonstration facility, and ICM agreed to assist us in running and maintaining the converted plant. We have used the demonstration plant to improve our biocatalysts and to develop processes for commercial-scale production of isobutanol. Under the commercialization agreement, as amended, ICM serves as our exclusive engineering, procurement and construction (“EPC”) contractor for the Retrofit of ethanol plants, and we serve as ICM’s exclusive technology partner for the production of butanols, pentanols and propanols from the fermentation of sugars. In August 2011, we entered into a work agreement with ICM. Pursuant to the terms of the work agreement, ICM provides EPC services for the Retrofit of ethanol plants.

Because ICM has designed a significant number of the current operating ethanol production facilities in the U.S., we believe that our exclusive alliance with ICM will provide us with a competitive advantage and allow us to more quickly achieve commercial-scale production of isobutanol. However, ICM may fail to fulfill its obligations to us under our agreements and under certain circumstances, such as a breach of confidentiality by us, can terminate the agreements. In addition, ICM may assign the agreements without our consent in connection with a change of control. Since adapting our technology to commercial-scale production of isobutanol and then Retrofitting ethanol plants to use our technology is a major part of our commercialization strategy, losing our exclusive alliance with ICM would slow our technological and commercial development. It could also force us to find a new contractor with less experience than ICM in designing and building ethanol plants, or to invest the time and resources necessary to Retrofit plants on our own. Such Retrofits may be less successful than if performed by ICM engineers, and Retrofitted plants might operate less efficiently than expected. This could substantially hinder our ability to expand our production capacity, and could severely impact our performance. If ICM fails to fulfill its obligations to us under our agreements and our competitors obtain access to ICM’s expertise, our ability to realize continued development and commercial benefits from our alliance could be affected. Accordingly, if we lose our exclusive alliance with ICM, if ICM terminates or breaches its agreements with us, or if ICM assigns its agreements with us to a competitor of ours or to a third party that is not willing to work with us on the same terms or commit the same resources, our business and prospects could be harmed.

Raising additional capital may cause dilution to our existing stockholders, restrict our operations or require us to relinquish rights to our technologies.

We may, subject to certain limitations in the indenture governing the 2013 Notes and the agreements governing our secured indebtedness with TriplePoint, seek additional capital through a combination of public and private equity offerings, debt financings, strategic partnerships and licensing arrangements. To the extent that we raise additional capital through the sale or issuance of equity, warrants or convertible debt securities, your ownership interest will be diluted, and the terms of such securities may include liquidation or other preferences that adversely affect your rights as a stockholder. If we raise capital through debt financing, it may involve agreements that include covenants further limiting or restricting our ability to take certain actions, such as incurring additional debt, making capital expenditures or declaring dividends. If we raise additional funds through strategic partnerships or licensing agreements with third parties, we may have to relinquish valuable rights to our technologies, or grant licenses on terms that are not favorable to us. If we are unable to raise additional funds when needed, we may be required to delay, limit, reduce or terminate our development and commercialization efforts.

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Our quarterly operating results may fluctuate in the future. As a result, we may fail to meet or exceed the expectations of investment research analysts or investors, which could cause our stock price to decline.

Our financial condition and operating results have varied significantly in the past and may continue to fluctuate from quarter to quarter and year to year in the future due to a variety of factors, many of which are beyond our control. Factors relating to our business that may contribute to these fluctuations are described elsewhere in this prospectus supplement, our Annual Report on Form 10-K for the year ended December 31, 2012, as amended, and other reports that we have filed with the SEC. Accordingly, the results of any prior quarterly or annual periods should not be relied upon as indications of our future operating performance.

Fluctuations in the price of corn and other feedstocks may affect our cost structure.

Our approach to the biofuels and chemicals markets will be dependent on the price of corn and other feedstocks that will be used to produce isobutanol. A decrease in the availability of plant feedstocks or an increase in the price may have a material adverse effect on our financial condition and operating results. At certain levels, prices may make these products uneconomical to use and produce, as we may be unable to pass the full amount of feedstock cost increases on to our customers.

The price and availability of corn and other plant feedstocks may be influenced by general economic, market and regulatory factors. These factors include weather conditions, farming decisions, government policies and subsidies with respect to agriculture and international trade, and global demand and supply. For example, corn prices may increase significantly in response to drought conditions in the Midwestern region of the U.S. and any concerns that a resulting decrease in the supply of corn could lead to the restriction of corn supplies, which in turn could cause further increases in the price of corn. The significance and relative impact of these factors on the price of plant feedstocks is difficult to predict, especially without knowing what types of plant feedstock materials we may need to use.

Fluctuations in the price and availability of natural gas may harm our performance.

The ethanol facilities that we have Retrofitted or plan to Retrofit to produce isobutanol, including the Agri-Energy Facility and the Redfield Facility, use significant amounts of natural gas to produce ethanol. After Retrofit with our GIFT^® technology, these facilities will continue to require natural gas to produce isobutanol. Accordingly, our business is dependent upon natural gas supplied by third parties. Should the price of natural gas increase, our performance could suffer. Likewise, disruptions in the supply of natural gas could have a material impact on our business and results of operations.

Fluctuations in petroleum prices and customer demand patterns may reduce demand for biofuels and bio-based chemicals.

We anticipate marketing our biofuel as an alternative to petroleum-based fuels. Therefore, if the price of oil falls, any revenues that we generate from biofuel products could decline, and we may be unable to produce products that are a commercially viable alternative to petroleum-based fuels. Additionally, demand for liquid transportation fuels, including biofuels, may decrease due to economic conditions or otherwise. We will encounter similar risks in the chemicals industry, where declines in the price of oil may make petroleum-based hydrocarbons less expensive, which could reduce the competitiveness of our bio-based alternatives.

Changes in the prices of distiller’s grains and iDGs™ could have a material adverse effect on our financial condition.

From September 2010 through May 2012, we sold distiller’s grains as a co-product from the production of ethanol at the Agri-Energy Facility. Similarly, we plan to sell distiller’s grains during any period in

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which the production of isobutanol is temporarily paused and our management decides, based on the then-current economic conditions for the production of ethanol, that the Agri-Energy Facility will be temporarily reverted to ethanol production. We may also sell distiller’s grains produced by other ethanol facilities that we acquire, enter into a joint venture or tolling arrangement with, or license to in the future. We also plan to sell the iDGs™ that will be produced as a co-product of our commercial isobutanol production. Distiller’s grains and iDGs™ compete with other animal feed products, and decreases in the prices of these other products could decrease the demand for and price of distiller’s grains and iDGs™. Additionally, we have not yet produced commercial iDGs™ and, as such, there is a risk that our iDGs™ may not meet market requirements. If the price of distiller’s grains and iDGs™ decreases or our iDGs™ do not meet market requirements, our revenue from the sale of distiller’s grains and future revenue from the sale of iDGs™ could suffer, which could have a material adverse effect on our financial condition.

To the extent that we produce ethanol at accessed plants before commencing isobutanol production, or during periods in which we make the strategic decision to revert to ethanol production, we will be vulnerable to fluctuations in the price of and cost to produce ethanol.

We believe that, like the Agri-Energy Facility, the other ethanol production facilities we access can continue to produce ethanol during most of the Retrofit process. In certain cases, we expect to obtain income from this ethanol production. Further, we have designed our isobutanol production technology to allow us to revert to ethanol production at certain facilities, such as the Agri-Energy Facility, when the economic conditions for ethanol production make such reversion desirable. Our earnings from ethanol revenue will be dependent on the price of, demand for and cost to produce ethanol. Decreases in the price of ethanol, whether caused by decreases in gasoline prices, changes in regulations, seasonal fluctuations or otherwise, will reduce our revenues, while increases in the cost of production will reduce our margins. Many of these risks, including fluctuations in feedstock costs and natural gas costs, are identical to risks we will face in the production of isobutanol. To the extent that ethanol production costs increase or price decreases, earnings from ethanol production could suffer, which could have a material adverse effect on our business.

Unfavorable weather conditions led to a smaller than expected corn harvest across affected areas of the U.S. Midwest region in the fall of 2012. This, along with smaller corn carryover in the last two crop years and higher export demand for corn led to higher corn prices during 2012 and the first half of 2013 and increased corn price volatility. The price of ethanol during that time did not keep pace with rising corn prices which resulted in lower and, in some instances negative, operating margins in the ethanol industry. As a result, during the fourth quarter of 2012, our management determined that the production of ethanol at the Agri-Energy Facility would not produce a positive margin versus maintaining the Agri-Energy Facility at idle. As a result, at December 31, 2012, we had an inventory of corn that was not being used while production at the Agri-Energy Facility remained paused. During 2013, we did not transition back to ethanol production because we were engaged in activities at the Agri-Energy Facility to optimize specific parts of our technology to further enhance isobutanol production rates. Accordingly, we opted to sell some of our corn inventory on hand to reduce corn inventory levels. Our sale of corn on the spot market subjects us to the risk that corn prices will be even higher when production at the facility permanently resumes and we need to reestablish our corn inventory levels. Our inability to rely on ethanol production as an alternative revenue source due to rising corn prices or otherwise could have a material adverse effect on our business, financial condition and results of operations.

Reductions or changes to existing regulations and policies may present technical, regulatory and economic barriers, all of which may significantly reduce demand for biofuels or our ability to supply isobutanol.

The market for biofuels is heavily influenced by foreign, federal, state and local government regulations and policies. For example, in 2007, the U.S. Congress passed an alternative fuels mandate that required

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nearly 14 billion gallons of liquid transportation fuels sold in 2011 to come from alternative sources, including biofuels, a mandate that grows to 36 billion gallons by 2022. Of this amount, a minimum of 21 billion gallons must be advanced biofuels as defined by the U.S. Congress. The EPA has set the renewable fuels volume requirement for 2013 at 16.55 billion gallons. In the U.S., and in a number of other countries, these regulations and policies have been modified in the past and may be modified again in the future. Any reduction in mandated requirements for fuel alternatives and additives to gasoline may cause the demand for biofuels to decline and deter investment in the research and development of biofuels. For example, the Energy and Commerce Committee of the U.S. House of Representatives has undertaken an assessment of the RFS program and has published five white papers on the subject during the current congressional period. This type of legislative activity can create concern in the marketplace about the long-term sustainability of governmental policies. The absence of tax credits, subsidies and other incentives in the U.S. and foreign markets for biofuels, or any inability of our customers to access such credits, subsidies and incentives, may adversely affect demand for our products, which would adversely affect our business. The resulting market uncertainty regarding current and future standards and policies may also affect our ability to develop new renewable products or to license our technologies to third parties and to sell products to our end customers.

Concerns associated with biofuels, including land usage, national security interests and food crop usage, continue to receive legislative, industry and public attention. This attention could result in future legislation, regulation and/or administrative action that could adversely affect our business. Any inability to address these requirements and any regulatory or policy changes could have a material adverse effect on our business, financial condition and results of operations.

Additionally, like the ethanol facilities that we Retrofit, our isobutanol plants will emit greenhouse gases. Any changes in state or federal emissions regulations, including the passage of cap-and-trade legislation or a carbon tax, could limit our production of isobutanol and iDGs™ and increase our operating costs, which could have a material adverse effect on our business, financial condition and results of operations.

If we engage in additional acquisitions, we will incur a variety of costs and may potentially face numerous risks that could adversely affect our business and operations.

If appropriate opportunities become available, we expect to acquire businesses, assets, technologies or products to enhance our business in the future. In connection with any future acquisitions, we could, subject to certain limitations in the indenture governing the 2013 Notes and the agreements governing our secured indebtedness with TriplePoint:

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issue additional equity securities which would dilute our current stockholders;

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incur substantial debt to fund the acquisitions; or

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assume significant liabilities.

Acquisitions involve numerous risks, including problems integrating the purchased operations, technologies or products, unanticipated costs and other liabilities, diversion of management’s attention from our core business, adverse effects on existing business relationships with current and/or prospective partners, customers and/or suppliers, risks associated with entering markets in which we have no or limited prior experience and potential loss of key employees. Other than our acquisition of Agri-Energy, we have not engaged in acquisitions in the past, and do not have experience in managing the integration process. Therefore, we may not be able to successfully integrate any businesses, assets, products, technologies or personnel that we might acquire in the future without a significant expenditure of operating, financial and management resources, if at all. The integration process could divert management time from focusing on operating our business, result in a decline in employee morale and cause retention issues to arise from changes in compensation, reporting relationships, future prospects or the direction of the business. In addition, we may acquire companies that have insufficient internal

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financial controls, which could impair our ability to integrate the acquired company and adversely impact our financial reporting. If we fail in our integration efforts with respect to acquisitions and are unable to efficiently operate as a combined organization, our business, financial condition and results of operations may be materially adversely affected.

If we engage in additional joint ventures, we will incur a variety of costs and may potentially face numerous risks that could adversely affect our business and operations.

If appropriate opportunities become available, we expect to enter into joint ventures with the owners of existing ethanol production facilities in order to acquire access to additional isobutanol production capacity. We currently anticipate that in each such joint venture, the ethanol producer would contribute access to its existing ethanol production facility and we would be responsible for Retrofitting such facility to produce isobutanol. Upon completion of the Retrofit, and in some cases the attainment of certain performance targets, both parties to the joint venture would receive a portion of the profits from the sale of isobutanol, consistent with our business model. In connection with these joint ventures, we could incur substantial debt to fund the Retrofit of the accessed facilities and we could assume significant liabilities.

Realizing the anticipated benefits of joint ventures, including projected increases to production capacity and additional revenue opportunities, involves a number of potential challenges. The failure to meet these challenges could seriously harm our financial condition and results of operations. Joint ventures are complex and time-consuming and we may encounter unexpected difficulties or incur unexpected costs related to such arrangements, including:

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difficulties negotiating joint venture agreements with favorable terms and establishing relevant performance metrics;

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difficulties completing the Retrofits of the accessed facilities using our integrated fermentation technology;

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the inability to meet applicable performance targets related to the production of isobutanol;

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difficulties obtaining the permits and approvals required to produce and sell our products in different geographic areas;

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complexities associated with managing the geographic separation of accessed facilities;

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diversion of management attention from ongoing business concerns to matters related to the joint ventures;

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difficulties maintaining effective relationships with personnel from different corporate cultures; and

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the inability to generate sufficient revenue to offset Retrofit costs.

Additionally, our joint venture partners may have liabilities or adverse operating issues that we fail to discover through due diligence prior to entering into the joint ventures. In particular, to the extent that our joint venture partners failed to comply with or otherwise violated applicable laws or regulations, or failed to fulfill their contractual obligations, we may suffer financial harm and/or reputational harm for these violations or otherwise be adversely affected.

Our joint venture partners may have significant amounts of existing debt and may not be able to service their existing debt obligations, which could cause the failure of a specific project and the loss by us of any investment we have made to Retrofit the facilities owned by the joint venture partner. In addition, if we are unable to meet specified performance targets related to the production of isobutanol at a facility owned by one of our joint venture partners, we may never become eligible to receive a portion of the profits of the joint venture and may be unable to recover the costs of Retrofitting the facility.

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Additionally, we plan to be the sole marketer for all isobutanol and co-products produced using our proprietary technology including, without limitation, all isobutanol that is produced by any facilities that we access via joint venture. Marketing agreements can be very complex and the obligations that we assume as the sole marketer of isobutanol may be time consuming. We have no experience marketing isobutanol on a commercial scale and we may fail to successfully negotiate marketing agreements in a timely manner or on favorable terms. If we fail to successfully market the isobutanol produced using our proprietary technology to refiners and chemical producers, our business, financial condition and results of operations will be materially adversely affected.

If we lose key personnel, including key management personnel, or are unable to attract and retain additional personnel, it could delay our product development programs and harm our research and development efforts, we may be unable to pursue partnerships or develop our own products and it may trigger an event of default under our loan agreement with TriplePoint.

Our business is complex and we intend to target a variety of markets. Therefore, it is critical that our management team and employee workforce are knowledgeable in the areas in which we operate. The loss of any key members of our management, including our named executive officers, or the failure to attract or retain other key employees who possess the requisite expertise for the conduct of our business, could prevent us from developing and commercializing our products for our target markets and entering into partnerships or licensing arrangements to execute our business strategy. In addition, the loss of any key scientific staff, or the failure to attract or retain other key scientific employees, could prevent us from developing and commercializing our products for our target markets and entering into partnerships or licensing arrangements to execute our business strategy. We may not be able to attract or retain qualified employees in the future due to the intense competition for qualified personnel among biotechnology and other technology-based businesses, particularly in the advanced biofuels area, or due to the limited availability of personnel with the qualifications or experience necessary for our renewable chemicals and advanced biofuels business. If we are not able to attract and retain the necessary personnel to accomplish our business objectives, we may experience staffing constraints that will adversely affect our ability to meet the demands of our partners and customers in a timely fashion or to support our internal research and development programs. In particular, our product and process development programs are dependent on our ability to attract and retain highly skilled scientists. Competition for experienced scientists and other technical personnel from numerous companies and academic and other research institutions may limit our ability to do so on acceptable terms. Additionally, certain changes in our management could trigger an event of default under the Amended Agri-Energy Loan Agreement and we could be forced to pay the outstanding balance of the loan(s) in full. All of our employees are at-will employees, meaning that either the employee or we may terminate their employment at any time.

Our planned activities will require additional expertise in specific industries and areas applicable to the products and processes developed through our technology platform or acquired through strategic or other transactions, especially in the end markets that we seek to penetrate. These activities will require the addition of new personnel, and the development of additional expertise by existing personnel. The inability to attract personnel with appropriate skills or to develop the necessary expertise could impair our ability to grow our business.

Our ability to compete may be adversely affected if we do not adequately protect our proprietary technologies or if we lose some of our intellectual property rights through costly litigation or administrative proceedings.

Our success will depend in part on our ability to obtain patents and maintain adequate protection of our intellectual property covering our technologies and products and potential products in the U.S. and other countries. We have adopted a strategy of seeking patent protection in the U.S. and in certain foreign countries with respect to certain of the technologies used in or relating to our products and processes. As such, as of September 30, 2013, we exclusively licensed rights to 94 issued patents and filed patent

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applications in the U.S. and in various foreign jurisdictions, and we owned rights to approximately 390 issued patents and filed patent applications in the U.S. and in various foreign jurisdictions. When and if issued, patents would expire at the end of their term and any patent would only provide us commercial advantage for a limited period of time, if at all. Our patent applications are directed to our enabling technologies and to our methods and products which support our business in the advanced biofuels and renewable chemicals markets. We intend to continue to apply for patents relating to our technologies, methods and products as we deem appropriate.

Only 26 of the patent applications that we have filed in the U.S. or in any foreign jurisdictions, and only certain of the patent applications filed by third parties in which we own rights, have been issued. A filed patent application does not guarantee a patent will issue and a patent issuing does not guarantee its validity, nor does it give us the right to practice the patented technology or commercialize the patented product. Third parties may have or obtain rights to “blocking patents” that could be used to prevent us from commercializing our products or practicing our technology. The scope and validity of patents and success in prosecuting patent applications involve complex legal and factual questions and, therefore, issuance, coverage and validity cannot be predicted with any certainty. Patents issuing from our filed applications may be challenged, invalidated or circumvented. Moreover, third parties could practice our inventions in secret and in territories where we do not have patent protection. Such third parties may then try to sell or import products made using our inventions in and into the U.S. or other territories and we may be unable to prove that such products were made using our inventions. Additional uncertainty may result from implementation of the Leahy-Smith America Invents Act, enacted in September 2011, as well as other potential patent reform legislation passed by the U.S. Congress and from legal precedent as handed down by the U.S. Court of Appeals for the Federal Circuit and the U.S. Supreme Court, as they determine legal issues concerning the scope, validity and construction of patent claims. Because patent applications in the U.S. and many foreign jurisdictions are typically not published until 18 months after filing, or in some cases not at all, and because publication of discoveries in the scientific literature often lags behind the actual discoveries, there is additional uncertainty as to the validity of any patents that may issue and the potential for “blocking patents” coming into force at some future date. Accordingly, we cannot ensure that any of our currently filed or future patent applications will result in issued patents, or even if issued, predict the scope of the claims that may issue in our and other companies’ patents. Given that the degree of future protection for our proprietary rights is uncertain, we cannot ensure that (i) we were the first to make the inventions covered by each of our filed applications, (ii) we were the first to file patent applications for these inventions, (iii) the proprietary technologies we develop will be patentable, (iv) any patents issued will be broad enough in scope to provide commercial advantage and prevent circumvention, and (v) competitors and other parties do not have or will not obtain patent protection that will block our development and commercialization activities.

These concerns apply equally to patents we have licensed, which may likewise be challenged, invalidated or circumvented, and the licensed technologies may be obstructed from commercialization by competitors’ “blocking patents.” In addition, we generally do not control the patent prosecution and maintenance of subject matter that we license from others. Generally, the licensors are primarily or wholly responsible for the patent prosecution and maintenance activities pertaining to the patent applications and patents we license, while we may only be afforded opportunities to comment on such activities. Accordingly, we are unable to exercise the same degree of control over licensed intellectual property as we exercise over our own intellectual property and we face the risk that our licensors will not prosecute or maintain it as effectively as we would like.

In addition, unauthorized parties may attempt to copy or otherwise obtain and use our products or technology. Monitoring unauthorized use of our intellectual property is difficult, particularly where, as here, the end products reaching the market generally do not reveal the processes used in their manufacture, and particularly in certain foreign countries where the local laws may not protect our proprietary rights as fully as in the U.S., so we cannot be certain that the steps we have taken in

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obtaining intellectual property and other proprietary rights will prevent unauthorized use of our technology. If competitors are able to use our technology without our authorization, our ability to compete effectively could be adversely affected. Moreover, competitors and other parties such as universities may independently develop and obtain patents for technologies that are similar to or superior to our technologies. If that happens, the potential competitive advantages provided by our intellectual property may be adversely affected. We may then need to license these competing technologies, and we may not be able to obtain licenses on reasonable terms, if at all, which could cause material harm to our business. Accordingly, litigation may be necessary for us to assert claims of infringement, enforce patents we own or license, protect trade secrets or determine the enforceability, scope and validity of the intellectual property rights of others.

Our commercial success also depends in part on not infringing patents and proprietary rights of third parties, and not breaching any licenses or other agreements that we have entered into with regard to our technologies, products and business. We cannot be certain that patents have not or will not issue to third parties that could block our ability to obtain patents or to operate our business as we would like, or at all. There may be patents in some countries that, if valid, may block our ability to commercialize products in those countries if we are unsuccessful in circumventing or acquiring rights to these patents. There may also be claims in patent applications filed in some countries that, if granted and valid, may also block our ability to commercialize products or processes in these countries if we are unable to circumvent or license them.

As is commonplace in the biotechnology industries, some of our directors, employees and consultants are or have been employed at, or associated with, companies and universities that compete with us or have or will develop similar technologies and related intellectual property. While employed at these companies, these employees, directors and consultants may have been exposed to or involved in research and technology similar to the areas of research and technology in which we are engaged. Though we have not received such a complaint, we may be subject to allegations that we, our directors, employees or consultants have inadvertently or otherwise used, misappropriated or disclosed alleged trade secrets or confidential or proprietary information of those companies. Litigation may be necessary to defend against such allegations and the outcome of any such litigation would be uncertain.

Under some of our research agreements, our partners share joint rights in certain intellectual property we develop. For example, under our development agreement with ICM, we have exclusive rights to all intellectual property developed within the defined scope of the project, but all other intellectual property developed pursuant to the agreement is to be jointly owned. Such provisions may limit our ability to gain commercial benefit from some of the intellectual property we develop, and may lead to costly or time-consuming disputes with parties with whom we have commercial relationships over rights to certain innovations.

If any other party has filed patent applications or obtained patents that claim inventions also claimed by us, we may have to participate in interference, derivation or other proceedings declared by the USPTO to determine priority of invention and, thus, the right to the patents for these inventions in the U.S. These proceedings could result in substantial cost to us even if the outcome is favorable. Even if successful, such a proceeding may result in the loss of certain claims. Even successful outcomes of such proceedings could result in significant legal fees and other expenses, diversion of management time and efforts and disruption in our business. Uncertainties resulting from initiation and continuation of any patent or related litigation could harm our ability to compete.

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If our biocatalysts, or the genes that code for our biocatalysts, are stolen, misappropriated or reverse engineered, others could use these biocatalysts or genes to produce competing products.

Third parties, including our contract manufacturers, customers and those involved in shipping our biocatalysts, may have custody or control of our biocatalysts. If our biocatalysts, or the genes that code for our biocatalysts, were stolen, misappropriated or reverse engineered, they could be used by other parties who may be able to reproduce these biocatalysts for their own commercial gain. If this were to occur, it would be difficult for us to discover or challenge this type of use, especially in countries with limited intellectual property protection.

We may not be able to enforce our intellectual property rights throughout the world.

The laws of some foreign countries do not protect intellectual property rights to the same extent as federal and state laws in the U.S. Many companies have encountered significant problems in protecting and enforcing intellectual property rights in certain foreign jurisdictions. The legal systems of certain countries, particularly certain developing countries, do not favor the enforcement of patents and other intellectual property protection, particularly those relating to bioindustrial technologies. This could make it difficult for us to stop the infringement of our patents or misappropriation of our other intellectual property rights. Proceedings to enforce our patents and other proprietary rights in foreign jurisdictions could result in substantial costs and divert our efforts and attention from other aspects of our business. Accordingly, our efforts to enforce our intellectual property rights in such countries may be inadequate to obtain a significant commercial advantage from the intellectual property that we develop.

Confidentiality agreements with employees and others may not adequately prevent disclosures of trade secrets and other proprietary information.

We rely in part on trade secret protection to protect our confidential and proprietary information and processes. However, trade secrets are difficult to protect. We have taken measures to protect our trade secrets and proprietary information, but these measures may not be effective. We require new employees and consultants to execute confidentiality agreements upon the commencement of an employment or consulting arrangement with us. These agreements generally require that all confidential information developed by the individual or made known to the individual by us during the course of the individual’s relationship with us be kept confidential and not disclosed to third parties. These agreements also generally provide that know-how and inventions conceived by the individual in the course of rendering services to us shall be our exclusive property. Nevertheless, these agreements may not be enforceable, our proprietary information may be disclosed, third parties could reverse engineer our biocatalysts and others may independently develop substantially equivalent proprietary information and techniques or otherwise gain access to our trade secrets. Costly and time-consuming litigation could be necessary to enforce and determine the scope of our proprietary rights, and failure to obtain or maintain trade secret protection could adversely affect our competitive business position. In addition, an unauthorized breach in our information technology systems may expose our trade secrets and other proprietary information to unauthorized parties.

We have received funding from U.S. government agencies, which could negatively affect our intellectual property rights.

Some of our research has been funded by grants from U.S. government agencies. When new technologies are developed with U.S. government funding, the government obtains certain rights in any resulting patents and technical data, generally including, at a minimum, a nonexclusive license authorizing the government to use the invention or technical data for noncommercial purposes. U.S. government funding must be disclosed in any resulting patent applications, and our rights in such inventions will normally be subject to government license rights, periodic progress reporting, foreign manufacturing restrictions and march-in rights. March-in rights refer to the right of the U.S. government, under certain limited circumstances, to require us to grant a license to technology developed under a government grant to a

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responsible applicant or, if we refuse, to grant such a license itself. March-in rights can be triggered if the government determines that we have failed to work sufficiently towards achieving practical application of a technology or if action is necessary to alleviate health or safety needs, to meet requirements of federal regulations or to give preference to U.S. industry. If we breach the terms of our grants, the government may gain rights to the intellectual property developed in our related research. The government’s rights in our intellectual property may lessen its commercial value, which could adversely affect our performance.

Our government grants are subject to uncertainty, which could harm our business and results of operations.

We have received various government grants, including a cooperative agreement, to complement and enhance our own resources. We may seek to obtain government grants and subsidies in the future to offset all or a portion of the costs of Retrofitting existing ethanol manufacturing facilities and the costs of our research and development activities. We cannot be certain that we will be able to secure any such government grants or subsidies. Any of our existing grants or new grants that we may obtain may be terminated, modified or recovered by the granting governmental body under certain conditions.

We may also be subject to audits by government agencies as part of routine audits of our activities funded by our government grants. As part of an audit, these agencies may review our performance, cost structures and compliance with applicable laws, regulations and standards. Funds available under grants must be applied by us toward the research and development programs specified by the granting agencies, rather than for all of our programs generally. If any of our costs are found to be allocated improperly, the costs may not be reimbursed and any costs already reimbursed may have to be refunded. Accordingly, an audit could result in an adjustment to our revenues and results of operations.

We may face substantial competition, which could adversely affect our performance and growth.

We may face substantial competition in the markets for isobutanol, polyester, rubber, plastics, fibers, other polymers and hydrocarbon fuels. Our competitors include companies in the incumbent petroleum-based industry as well as those in the nascent biorenewable industry. The incumbent petroleum-based industry benefits from a large established infrastructure, production capability and business relationships. The incumbents’ greater resources and financial strength provide significant competitive advantages that we may not be able to overcome in a timely manner. Academic and government institutions may also develop technologies which will compete with us in the chemicals, solvents and blendstock markets.

The biorenewable industry is characterized by rapid technological change. Our future success will depend on our ability to maintain a competitive position with respect to technological advances. Technological development by others may impact the competitiveness of our products in the marketplace. Competitors and potential competitors who have greater resources and experience than we do may develop products and technologies that make ours obsolete or may use their greater resources to gain market share at our expense.

In the production of isobutanol, we face competition from Butamax. Additionally, a number of companies including Cathay Industrial Biotech, Ltd., Green Biologics Ltd., METabolic Explorer, S.A., Eastman Chemical Company (which acquired TetraVitae Bioscience, Inc. in November 2011) and Cobalt Technologies, Inc. are developing n-butanol production capability from a variety of renewable feedstocks.

In the polyester, rubber, plastics, fibers and other polymers markets, we face competition from incumbent petroleum-derived products, other renewable isobutanol producers and renewable n-butanol producers. Our competitive position versus the incumbent petroleum-derived products and other renewable butanol producers may not be favorable. Petroleum-derived products have dominated the

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market for many years and there is substantial existing infrastructure for production from petroleum sources, which may impede our ability to establish a position in these markets. Other isobutanol and n-butanol companies may develop technologies that prove more effective than our isobutanol production technology, or such companies may be more adept at marketing their production. Additionally, one small company in France, Global Bioenergies, S.A., is pursuing the production of isobutylene from renewable carbohydrates directly. Since conversion of isobutanol to butenes such as isobutylene is a key step in producing many polyester, rubber, plastics, fibers and other polymers from our isobutanol, this direct production of renewable isobutylene, if successful, could limit our opportunities in these markets.

In the gasoline blendstock market, we will compete with renewable ethanol producers (including those working to produce ethanol from cellulosic feedstocks), producers of alkylate from petroleum and producers of other blendstocks, all of whom may reduce our ability to obtain market share or maintain our price levels. For example, Coskata, Inc. is developing a hybrid thermochemical-biocatalytic process to produce ethanol from a variety of feedstocks. If any of these competitors succeed in producing blendstocks more efficiently, in higher volumes or offering superior performance than our isobutanol, our financial performance may suffer. Furthermore, if our competitors have more success marketing their products or reach development or supply agreements with major customers, our competitive position may also be harmed.

In the production of other biofuels, key competitors include Shell Oil Company, BP, DuPont-Danisco Cellulosic Ethanol LLC, Abengoa Bioenergy, S.A., POET, LLC, ICM, Mascoma Corporation, Inbicon A/S, INEOS New Planet BioEnergy LLC, Coskata, Inc., Archer Daniels Midland Company, BlueFire Ethanol, Inc., KL Energy Corporation, ZeaChem Inc., Iogen Corporation, Qteros, Inc., AE Biofuels, Inc. and many smaller start-up companies. If these companies are successful in establishing low cost cellulosic ethanol or other fuel production, it could negatively impact the market for our isobutanol as a gasoline blendstock.

In the markets for the hydrocarbon fuels that we plan to produce from our isobutanol, we will face competition from the incumbent petroleum-based fuels industry. The incumbent petroleum-based fuels industry makes the vast majority of the world’s gasoline, jet and diesel fuels and blendstocks. It is a mature industry with a substantial base of infrastructure for the production and distribution of petroleum-derived products. The size, established infrastructure and significant resources of many companies in this industry may put us at a substantial competitive disadvantage and delay or prevent the establishment and growth of our business in the market for hydrocarbon fuels.

Biofuels companies may also provide substantial competition in the hydrocarbon fuels market. With respect to production of renewable gasoline, biofuels competitors are numerous and include both large established companies and numerous start-ups. For example, Virent Energy Systems, Inc. has developed a process for making gasoline and gasoline blendstocks and Kior, Inc. has developed a technology platform to convert biomass into renewable crude oil. Many other competitors may do so as well. In the jet fuel market, we will face competition from companies such as Synthetic Genomics, Inc., Solazyme, Inc., Sapphire Energy, Inc. and Exxon-Mobil Corporation that are pursuing production of jet fuel from algae-based technology. LS9, Inc. (“LS9”) and others are also targeting production of jet fuels from renewable biomass. We may also face competition from companies working to produce jet fuel from hydrogenated fatty acid methyl esters. In the diesel fuels market, competitors such as Amyris Biotechnologies, Inc. and LS9 have developed technologies for production of alternative hydrocarbon diesel fuel.

In the polyester, rubber, plastics, fibers and other polymers markets and the hydrocarbon fuels market, we expect to face vigorous competition from existing technologies. The companies we may compete with may have significantly greater access to resources, far more industry experience and/or more established sales and marketing networks. Additionally, since we do not plan to produce most of these products directly, we depend on the willingness of potential customers to purchase and convert our isobutanol

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into their products. These potential customers generally have well-developed manufacturing processes and arrangements with suppliers of the chemical components of their products and may have a resistance to changing these processes and components. These potential customers frequently impose lengthy and complex product qualification procedures on their suppliers, influenced by consumer preference, manufacturing considerations such as process changes and capital and other costs associated with transitioning to alternative components, supplier operating history, regulatory issues, product liability and other factors, many of which are unknown to, or not well understood by, us. Satisfying these processes may take many months or years. If we are unable to convince these potential customers that our isobutanol is comparable or superior to the alternatives that they currently use, we will not be successful in entering these markets and our business will be adversely affected.

We also face challenges in marketing our isobutanol. Though we intend to enhance our competitiveness through partnerships and joint development agreements, some competitors may gain an advantage by securing more valuable partnerships for developing their hydrocarbon products than we are able to obtain. Such partners could include major petrochemical, refiner or end-user companies. Additionally, petrochemical companies may develop alternative pathways for hydrocarbon production that may be less expensive, and may utilize more readily available infrastructure than that used to convert our isobutanol into hydrocarbon products.

We plan to enter into partnerships through which we will sell significant volumes of our isobutanol to partners who will convert it into useful hydrocarbons or use it as a fuel or as a gasoline blendstock. However, if any of these partners instead negotiate supply agreements with other buyers for the isobutanol they purchase from us, or sell it into the open market, they may become competitors of ours in the field of isobutanol sales. This could significantly reduce our profitability and hinder our ability to negotiate future supply agreements for our isobutanol, which could have an adverse effect on our performance.

Our ability to compete successfully will depend on our ability to develop proprietary products that reach the market in a timely manner and are technologically superior to and/or are less expensive than other products on the market. Many of our competitors have substantially greater production, financial, research and development, personnel and marketing resources than we do. In addition, certain of our competitors may also benefit from local government subsidies and other incentives that are not available to us. As a result, our competitors may be able to develop competing and/or superior technologies and processes, and compete more aggressively and sustain that competition over a longer period of time than we could. Our technologies and products may be rendered obsolete or uneconomical by technological advances or entirely different approaches developed by one or more of our competitors. As more companies develop new intellectual property in our markets, the possibility of a competitor acquiring patent or other rights that may limit our products or potential products increases, which could lead to litigation. Furthermore, to secure purchase agreements from certain customers, we may be required to enter into exclusive supply contracts, which could limit our ability to further expand our sales to new customers. Likewise, major potential customers may be locked into long-term, exclusive agreements with our competitors, which could inhibit our ability to compete for their business.

In addition, various governments have recently announced a number of spending programs focused on the development of clean technologies, including alternatives to petroleum-based fuels and the reduction of carbon emissions. Such spending programs could lead to increased funding for our competitors or a rapid increase in the number of competitors within those markets.

Our limited resources relative to many of our competitors may cause us to fail to anticipate or respond adequately to new developments and other competitive pressures. This failure could reduce our competitiveness and market share, adversely affect our results of operations and financial position and prevent us from obtaining or maintaining profitability.

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The terms of the Amended Agri-Energy Loan Agreement and the indentures governing the Convertible Notes may restrict our ability to engage in certain transactions and settlement of the Convertible Notes through early conversion could result in further dilution to our existing stockholders.

In August 2010, Gevo, Inc. entered into a loan and security agreement with TriplePoint (the “Gevo Loan Agreement”), pursuant to which the Company borrowed $5.0 million, which was repaid in full in July 2012. Also in August 2010, our wholly owned subsidiary, Gevo Development, borrowed $12.5 million to finance its acquisition of Agri-Energy pursuant to a loan and security agreement with TriplePoint (the “Original Agri-Energy Loan Agreement”), and immediately following such acquisition Agri-Energy assumed such obligations as borrower. In October 2011, the Original Agri-Energy Loan Agreement was amended and restated (the “Amended Agri-Energy Loan Agreement”) to provide Agri-Energy with additional term loan facilities of up to $15.0 million (the “New Loan”) to pay a portion of the costs, expenses, and other amounts associated with the retrofit of the Agri-Energy Facility to produce isobutanol. In October 2011, Agri-Energy borrowed a portion of the New Loan in the amount of $10.0 million under the Amended Agri-Energy Loan Agreement. On January 6, 2012, Agri-Energy borrowed an additional $5.0 million under the Amended Agri-Energy Loan Agreement, bringing the total borrowed under the New Loan at September 30, 2013 to $15.0 million. Concurrently with the execution of the Amended Agri-Energy Loan Agreement, Gevo, Inc. entered into an amendment to its security agreement with TriplePoint (the “Gevo Security Agreement”), which secures its guarantee of Agri-Energy’s obligations (including up to $32.5 million in term loans) under the Amended Agri-Energy Loan Agreement. Pursuant to the terms of the Amended Agri-Energy Loan Agreement, we cannot engage in certain actions, including disposing of certain assets, granting or otherwise allowing the imposition of a lien against certain assets, incurring certain kinds of additional indebtedness or acquiring or merging with other entities unless we receive the prior approval of TriplePoint. If TriplePoint does not consent to any of the actions that we desire to take, we could be prohibited from engaging in transactions which could be beneficial to our business and our stockholders or could be forced to pay the outstanding balance of the loan in full.

In June 2012, Gevo, Inc. entered into an amendment (the “Security Agreement Amendment”) to the Gevo Security Agreement and an amendment to the Gevo Loan Agreement which (i) permit Agri-Energy to make dividend payments and distributions to us for certain defined purposes related to the 2012 Notes, (ii) added as an event of default the payment, repurchase or redemption of the 2012 Notes or of amounts payable in connection therewith other than certain permitted payments related to the 2012 Notes, including regularly scheduled interest payments, (iii) added a negative covenant whereby we may not incur any indebtedness other than as permitted under the Security Agreement Amendment and (iv) added a prohibition on making any Coupon Make-Whole Payments upon conversion of the 2012 Notes in cash prior to the payment of all remaining outstanding obligations in full under the Amended Agri-Energy Loan Agreement. If we take any of the actions prohibited by the amendments, we could be forced to pay the outstanding balance of the loan in full.

In anticipation of this offering and the concurrent offering of senior note units, the Company will enter into new and/or further amended agreements with TriplePoint to, among other things:

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permit the offering of the 2013 Notes and the incurrence of indebtedness by the Company under the 2013 Notes;

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permit the offering of warrants hereunder and in the concurrent offering and the incurrence of indebtedness by the Company under such warrants;

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grant TriplePoint a lien and security interest in all of the intellectual property of the Company;

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expand the events of default to add as events of default (A) the payment, repurchase or redemption of the 2013 Notes or of amounts payable in connection therewith other than certain permitted payments related to the 2013 Notes, including regularly scheduled interest payments and (B) the repurchase of the warrants;

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•

expand the limitations and restrictions on cash payments and redemptions (including any Coupon Make-Whole Payments) that are applicable to the 2012 Notes to apply equally to also restrict such events in connection with the 2013 Notes issued in the concurrent offering of senior note units;

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contingent upon the satisfaction of certain conditions precedent (including (A) receipt by the Company of not less than $15.0 million in some combination of net cash proceeds from this offering of common stock units and the concurrent offering of senior note units, and (B) a requirement that not less than $5.1 million be applied to prepay indebtedness owed to TriplePoint pursuant to Promissory Note 0647-GC-01-01 (the “Payoff Note”)), to:

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permit the End of Term Payment (as designated in the Payoff Note) to be payable in 12 equal monthly installments commencing on January 1, 2014 and ending on December 1, 2014, rather than requiring such payment on the date of prepayment of the Payoff Note;

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waive any prepayment premium (but not any End of Term Payment) with respect to the Payoff Note, Promissory Note 0647-GC-03-01 and Promissory Note 0647-GC-03-02;

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re-price the three outstanding warrants to purchase common stock of the Company that are held by TriplePoint, which as of November 30, 2013 are exercisable in the aggregate for 388,441 shares of the Company’s common stock, to reflect an exercise price equal to the closing price of the Company’s common stock on the NASDAQ Global Market as of the trading date immediately prior to the closing of the offering of the senior note units;

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waive the requirement for Agri-Energy to make principal amortization payments on the New Loan (including Promissory Note 0647-GC-03-01, and Promissory Note 0647-GC-03-02) during the period from the date the conditions above are satisfied through December 31, 2014 (the “Restructure Period”);

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raise the interest rates under the New Loan (including Promissory Note 0647-GC-03-01 and Promissory Note 0647-GC-03-02) to 13% during the Restructure Period (provided that such rate will return to 11% following the Restructure Period so long as no event of default under the Amended Agri-Energy Loan Agreement shall be continuing on the last day of the Restructure Period); and

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during the period beginning January 1, 2015, and continuing through and including the final monthly installment due under any promissory note issued for the benefit of TriplePoint under the Amended Agri-Energy Loan Agreement, adjust the monthly payment due and payable to 50% of the fully amortizing amount of principal and interest otherwise due and payable for such month, applied first to outstanding accrued interest and then to principal, with the remaining 50% portion of such required payments of principal and interest for such month accruing and made due and payable at the time of the final monthly installment; and

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permit dividends and distributions to (i) pay regularly scheduled interest on the Convertible Notes, (ii)(a) convert of all or any portion of indebtedness or such amounts payable under the terms of the Convertible Notes or certain indebtedness incurred to refinance the Convertible Notes (including any Coupon Make-Whole Payment) into common stock of the Company and/or Gevo Development in accordance with the terms of the documents governing the respective Convertible Notes or such refinancing indebtedness and (b) make cash payments in lieu of issuing fractional shares in connection with any conversion described in clause (ii)(a) above or in connection with the exercise of any warrant, and (iii) permit certain exchanges of indebtedness under the 2012 Notes for indebtedness under the 2013 Notes; provided that the exchange satisfies certain conditions.

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As of September 30, 2013, the aggregate outstanding principal and final payments under the Amended Agri-Energy Loan Agreement was approximately $18.9 million.

If holders of our Convertible Notes elect to convert (i) some or all of their 2012 Notes prior to July 1, 2017, or (ii) some or all of their 2013 Notes on or after June 1, 2014 and prior to December 1, 2018, and we have amounts of principal outstanding to TriplePoint, any issuances of stock that we make in satisfaction of the Coupon Make-Whole Payments due to such note holders will cause dilution to our existing stockholders because certain limitations in the agreements governing our secured indebtedness with TriplePoint will require us to make such payments in shares of common stock rather than cash. As of September 30, 2013, we have issued 2,957,775 shares of our common stock in satisfaction of Coupon Make-Whole Payments due in connection with the conversion of the 2012 Notes.

The indenture governing the 2013 Notes will contain negative covenants that, subject in each case to certain exceptions, generally will limit our ability to incur additional indebtedness, incur liens and issue preferred stock.

If a Fundamental Change occurs prior to the maturity date of the Convertible Notes, holders of the Convertible Notes will have the right, at their option, to require us to repurchase all or a portion of their Convertible Notes. In addition, if a Fundamental Change occurs prior to the maturity date of the Convertible Notes, we will in some cases be required to increase the conversion rate for a holder that elects to convert its Convertible Notes in connection with such Fundamental Change. In addition, the indentures governing the Convertible Notes prohibit us from engaging in certain mergers or acquisitions unless, among other things, the surviving entity assumes our obligations under the Convertible Notes. If an extraordinary transaction occurs, holders of warrants will have the right, at their option, to require us to repurchase the unexercised portion of such warrants for an amount in cash equal to the value of the warrants, as determined in accordance with the Black Scholes option pricing model and the terms of the warrants. These and other provisions could prevent or deter a third party from acquiring us, even where the acquisition could be beneficial to you.

Business interruptions could delay us in the process of developing our products and could disrupt our sales.

We are vulnerable to natural disasters and other events that could disrupt our operations, such as riots, civil disturbances, war, terrorist acts, floods, infections in our laboratory or production facilities or those of our contract manufacturers and other events beyond our control. We do not have a detailed disaster recovery plan. In addition, we may not carry sufficient business interruption insurance to compensate us for losses that may occur. Any losses or damages we incur could have a material adverse effect on our cash flows and success as an overall business. Furthermore, ICM may terminate our commercialization agreement if a force majeure event interrupts our operations for a specified period of time.

We engage in hedging transactions, which could harm our business.

We have engaged in hedging transactions to offset some of the effects of volatility in commodity prices. We generally follow a policy of using exchange-traded futures contracts to reduce our net position in agricultural commodity inventories and forward purchase contracts to manage price risk. Hedging activities may cause us to suffer losses, such as if we purchase a position in a declining market or sell a position in a rising market. Furthermore, hedging exposes us to the risk that we may have under- or over-estimated our need for a specific commodity or that the other party to a hedging contract may default on its obligation. If there are significant swings in commodity prices, or if we purchase more corn for future delivery than we can process, we may have to pay to terminate a futures contract, resell unneeded corn inventory at a loss, or produce our products at a loss, all of which would have a material adverse effect on our financial performance. We may vary the hedging strategies we undertake, which could leave us more vulnerable to increases in commodity prices or decreases in the prices of isobutanol, distiller’s grains, iDGs™ or ethanol. Losses from hedging activities and changes in hedging strategy could have a material adverse effect on our operations.

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Ethical, legal and social concerns about genetically engineered products and processes, and similar concerns about feedstocks grown on land that could be used for food production, could limit or prevent the use of our products, processes and technologies and limit our revenues.

Some of our processes involve the use of genetically engineered organisms or genetic engineering technologies. Additionally, our feedstocks may be grown on land that could be used for food production, which subjects our feedstock sources to “food versus fuel” concerns. If we are not able to overcome the ethical, legal and social concerns relating to genetic engineering or food versus fuel, our products and processes may not be accepted. Any of the risks discussed below could result in increased expenses, delays or other impediments to our programs or the public acceptance and commercialization of products and processes dependent on our technologies or inventions.

Our ability to develop and commercialize one or more of our technologies, products, or processes could be limited by the following factors:

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public attitudes about the safety and environmental hazards of, and ethical concerns over, genetic research and genetically engineered products and processes, which could influence public acceptance of our technologies, products and processes;

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public attitudes regarding and potential changes to laws governing ownership of genetic material, which could harm our intellectual property rights with respect to our genetic material and discourage others from supporting, developing or commercializing our products, processes and technologies;

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public attitudes and ethical concerns surrounding production of feedstocks on land which could be used to grow food, which could influence public acceptance of our technologies, products and processes;

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governmental reaction to negative publicity concerning genetically engineered organisms, which could result in greater government regulation of genetic research and derivative products; and

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governmental reaction to negative publicity concerning feedstocks produced on land which could be used to grow food, which could result in greater government regulation of feedstock sources.

The subjects of genetically engineered organisms and food versus fuel have received negative publicity, which has aroused public debate. This adverse publicity could lead to greater regulation and trade restrictions on imports of genetically engineered products or feedstocks grown on land suitable for food production.

The biocatalysts that we develop have significantly enhanced characteristics compared to those found in naturally occurring enzymes or microbes. While we produce our biocatalysts only for use in a controlled industrial environment, the release of such biocatalysts into uncontrolled environments could have unintended consequences. Any adverse effect resulting from such a release could have a material adverse effect on our business and financial condition, and we may be exposed to liability for any resulting harm.

Compliance with stringent laws and regulations may be time consuming and costly, which could adversely affect the commercialization of our biofuels products and related co-products.

Any biofuels developed using our technologies will need to meet a significant number of regulations and standards, including regulations imposed by the U.S. Department of Transportation, the EPA, the FDA, the FAA, various state agencies and others. Any failure to comply, or delays in compliance, with the various existing and evolving industry regulations and standards could prevent or delay the commercialization of any biofuels developed using our technologies and subject us to fines and other penalties.

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We use hazardous materials in our business and we must comply with environmental laws and regulations. Any claims relating to improper handling, storage or disposal of these materials or noncompliance with applicable laws and regulations could be time consuming and costly and could adversely affect our business and results of operations.

Our research and development processes involve the use of hazardous materials, including chemical, radioactive and biological materials. Our operations also produce hazardous waste. We cannot eliminate entirely the risk of accidental contamination or discharge and any resultant injury from these materials. Federal, state and local laws and regulations govern the use, manufacture, storage, handling and disposal of, and human exposure to, these materials. We may be sued for any injury or contamination that results from our use or the use by third parties of these materials, and our liability may exceed our total assets. Although we believe that our activities conform in all material respects with environmental laws, there can be no assurance that violations of environmental, health and safety laws will not occur in the future as a result of human error, accident, equipment failure or other causes. Compliance with applicable environmental laws and regulations may be expensive, and the failure to comply with past, present, or future laws could result in the imposition of fines, third-party property damage, product liability and personal injury claims, investigation and remediation costs, the suspension of production or a cessation of operations, and our liability may exceed our total assets. Liability under environmental laws can be joint and several and without regard to comparative fault. Environmental laws could become more stringent over time imposing greater compliance costs and increasing risks and penalties associated with violations, which could impair our research, development or production efforts and harm our business.

As isobutanol has not previously been used as a commercial fuel in significant amounts, its use subjects us to product liability risks, and we may have difficulties obtaining product liability insurance.

Isobutanol has not previously been used as a commercial fuel and research regarding its impact on engines and distribution infrastructure is ongoing. Though we intend to test our isobutanol further before its commercialization, there is a risk that it may damage engines or otherwise fail to perform as expected. If isobutanol degrades the performance or reduces the lifecycle of engines, or causes them to fail to meet emissions standards, market acceptance could be slowed or stopped, and we could be subject to product liability claims. Furthermore, due to isobutanol’s lack of commercial history as a fuel, we are uncertain as to whether we will be able to acquire product liability insurance on reasonable terms, or at all. A significant product liability lawsuit could substantially impair our production efforts and could have a material adverse effect on our business, reputation, financial condition and results of operations.

During the ordinary course of business, we may become subject to lawsuits or indemnity claims, which could materially and adversely affect our business and results of operations.

From time to time, we may in the ordinary course of business be named as a defendant in lawsuits, claims and other legal proceedings. These actions may seek, among other things, compensation for alleged personal injury, worker’s compensation, employment discrimination, breach of contract, property damages, civil penalties and other losses of injunctive or declaratory relief. In the event that such actions or indemnities are ultimately resolved unfavorably at amounts exceeding our accrued liability, or at material amounts, the outcome could materially and adversely affect our reputation, business and results of operations. In addition, payments of significant amounts, even if reserved, could adversely affect our liquidity position.

We may not be able to use some or all of our net operating loss carry-forwards to offset future income.

We have net operating loss carryforwards due to prior period losses, which if not utilized will begin to expire at various times over the next 20 years. If we are unable to generate sufficient taxable income to utilize our net operating loss carryforwards, these carryforwards could expire unused and be unavailable to offset future income tax liabilities.

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In addition, under Section 382 of the Internal Revenue Code of 1986, as amended, a corporation that undergoes an “ownership change” (generally defined as a greater than 50% change (by value) in its equity ownership over a three-year period) is subject to limitation on its ability to utilize its pre-change net operating loss carry-forwards, or net operating losses, to offset future taxable income. We may have experienced one or more ownership changes in prior years, and the issuance of shares in connection with our initial public offering may itself have triggered an ownership change. In addition, future changes in our stock ownership, which may be outside of our control, may trigger an ownership change, as may future equity offerings or acquisitions that have equity as a component of the purchase price. If an ownership change has occurred or does occur in the future, our ability to utilize our net operating losses to offset income if we attain profitability may be limited.

Enacted and proposed changes in securities laws and regulations have increased our costs and may continue to increase our costs in the future.

In recent years, there have been several changes in laws, rules, regulations and standards relating to corporate governance and public disclosure, including the Dodd-Frank Wall Street Reform and Consumer Protection Act (the “Dodd-Frank Act”), the Sarbanes-Oxley Act of 2002 and various other new regulations promulgated by the SEC and rules promulgated by the national securities exchanges.

The Dodd-Frank Act, enacted in July 2010, expands federal regulation of corporate governance matters and imposes requirements on publicly-held companies, including us, to, among other things, provide stockholders with a periodic advisory vote on executive compensation and also requires compensation committee reforms and enhanced pay-for-performance disclosures. While some provisions of the Dodd-Frank Act are effective upon enactment, others will be implemented upon the SEC’s adoption of related rules and regulations. The scope and timing of the adoption of such rules and regulations is uncertain and accordingly, the cost of compliance with the Dodd-Frank Act is also uncertain.

These and other new or changed laws, rules, regulations and standards are, or will be, subject to varying interpretations in many cases due to their lack of specificity. As a result, their application in practice may evolve over time as new guidance is provided by regulatory and governing bodies, which could result in continuing uncertainty regarding compliance matters and higher costs necessitated by ongoing revisions to disclosure and governance practices. Our efforts to comply with evolving laws, regulations and standards are likely to continue to result in increased general and administrative expenses and a diversion of management time and attention from revenue-generating activities to compliance activities. Further, compliance with new and existing laws, rules, regulations and standards may make it more difficult and expensive for us to maintain director and officer liability insurance, and we may be required to accept reduced coverage or incur substantially higher costs to obtain coverage. Members of our board of directors and our principal executive officer and principal financial officer could face an increased risk of personal liability in connection with the performance of their duties. As a result, we may have difficulty attracting and retaining qualified directors and executive officers, which could harm our business. We continually evaluate and monitor regulatory developments and cannot estimate the timing or magnitude of additional costs we may incur as a result of such developments.

If we fail to maintain an effective system of internal controls, we might not be able to report our financial results accurately or prevent fraud; in that case, our stockholders could lose confidence in our financial reporting, which would harm our business and could negatively impact the price of our stock.

Effective internal controls are necessary for us to provide reliable financial reports and prevent fraud. In addition, Section 404 of the Sarbanes-Oxley Act of 2002 (“Section 404”) requires us to evaluate and report on our internal control over financial reporting and have our principal executive officer and principal financial officer certify as to the accuracy and completeness of our financial reports. The process of maintaining our internal controls and complying with Section 404 is expensive and time consuming, and requires significant attention of management. We cannot be certain that these measures

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will ensure that we maintain adequate controls over our financial processes and reporting in the future. Even if we conclude that our internal control over financial reporting provides reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles, because of their inherent limitations, our internal controls over financial reporting may not prevent or detect fraud or misstatements. Failure to maintain required controls or implement new or additional controls as circumstances warrant, or difficulties encountered in maintaining or implementing controls, could harm our results of operations or cause us to fail to meet our reporting obligations.

Our management has concluded that there are no material weaknesses in our internal controls over financial reporting as of September 30, 2013. However, there can be no assurance that our controls over financial processes and reporting will be effective in the future or that additional material weaknesses or significant deficiencies in our internal controls will not be discovered in the future. If we, or our independent registered public accounting firm, discover a material weakness, the disclosure of that fact, even if quickly remedied, could reduce the market’s confidence in our financial statements and harm our stock price. In addition, a delay in compliance with Section 404 could subject us to a variety of administrative sanctions, including SEC action, ineligibility for short form resale registration, the suspension or delisting of our common stock from the stock exchange on which it is listed and the inability of registered broker-dealers to make a market in our common stock, which would further reduce our stock price and could harm our business.

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CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus supplement, the accompanying prospectus and the documents incorporated by reference herein and therein contain forward-looking statements within the meaning of Section 27A of the Securities Act and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). These statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, levels of activity, performance or achievements to differ materially from those expressed or implied by the forward-looking statements. Forward-looking statements may include, but are not limited to, statements relating to the achievement of advances in our technology platform, the success of our Retrofit production model, the availability of suitable and cost-competitive feedstocks, our ability to gain market acceptance for our products, the expected cost-competitiveness and relative performance attributes of our isobutanol and the products derived from it, additional competition, changes in economic conditions, the future price and volatility of petroleum and products derived from petroleum and statements regarding our intended uses of the proceeds of the securities offered hereby. In some cases, you can identify forward-looking statements by terminology such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “believe,” “estimate,” “predict,” “potential” or “continue,” the negative of such terms or other comparable terminology.

Forward-looking statements reflect our current views about future events, are based on assumptions, and are subject to known and unknown risks and uncertainties. Many important factors could cause actual results or achievements to differ materially from the results, performance or achievements expressed in or implied by our forward-looking statements, including the factors listed below. Many of the factors that will determine future results, performance or achievements are beyond our ability to control or predict. The following are important factors, among others, that could cause actual results, performance or achievements to differ materially from the results or achievements reflected in our forward-looking statements:

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our inability to successfully commercialize isobutanol and the products derived from it;

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our inability to produce full-scale commercial quantities of isobutanol in a timely and economic manner;

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our inability to effectively use the net proceeds from this offering and the concurrent offering of senior note units, if any;

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unexpected delays, operational difficulties, cost-overruns or failures in the Retrofit process;

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our failure to successfully identify and acquire access to additional facilities suitable for efficient Retrofitting;

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our failure to market our isobutanol to potential customers;

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fluctuations in the market price of petroleum;

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fluctuations in the market price of corn and other feedstocks;

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our inability to obtain regulatory approval for the use of our isobutanol in our target markets;

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our failure to adequately protect our intellectual property, or the loss of some of our intellectual property rights through costly litigation or administrative proceedings;

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our failure to transition our preliminary commitments into definitive supply and distribution agreements or to negotiate sufficient long-term supply agreements for our production of isobutanol; and

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general economic conditions and inflation, interest rate movements and access to capital.

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The forward-looking statements contained herein reflect our views and assumptions only as of the date such forward-looking statements are made. You should not place undue reliance on forward-looking statements. Except as required by law, we assume no responsibility for updating any forward-looking statements nor do we intend to do so. Our actual results, performance or achievements could differ materially from the results expressed in, or implied by, these forward-looking statements. The risks included in this section are not exhaustive. Additional factors that could cause actual results to differ materially from those described in the forward-looking statements are set forth in the section entitled “Risk Factors” beginning on page S-14 of this prospectus supplement.

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USE OF PROCEEDS

We expect the net proceeds from this offering to be approximately $ million (or $ million if the underwriter exercises in full its option to purchase additional shares of common stock and warrants), after deducting underwriting discounts and commissions, as described in “Underwriting,” and estimated offering expenses payable by us. In addition, we estimate that the net proceeds from the concurrent offering of senior note units, after deducting estimated underwriting discounts and commissions and offering expenses, will be approximately $ million (or approximately $ million if the underwriter for the concurrent offering of senior note units exercises in full its option to purchase additional 2013 Notes and warrants). However, this offering is not contingent upon the concurrent offering of senior note units and we cannot assure you that we will complete the concurrent offering of senior note units.

We currently intend to use all or a portion of the net proceeds of this offering and the concurrent offering of senior note units, if any, together with existing cash and cash equivalents, to ramp up startup production and sales at the Agri-Energy Facility. We may also use a portion of the net proceeds of this offering and the concurrent offering of senior note units, if any, to fund working capital and other general corporate purposes, which may include paying off certain of our long-term debt obligations and expenses associated with litigation.

As of the date of this prospectus supplement, we cannot specify with certainty all of the particular uses of the proceeds from this offering and the concurrent offering of senior note units, if any. Accordingly, we will retain broad discretion over the use of such proceeds. Pending the use of the net proceeds from this offering and the concurrent offering of senior note units, if any, as described above, we intend to invest the net proceeds in demand deposit accounts.

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CAPITALIZATION

The following table sets forth our cash and cash equivalents and stockholders’ equity as of September 30, 2013:

•

on an actual basis;

•

as adjusted to give effect to the receipt of estimated net proceeds of $ from this offering at an offering price of $ per common stock unit after deducting estimated underwriting discounts and estimated offering expenses payable by us, and the application of the net proceeds therefrom as described above under the heading “Use of Proceeds;” and

•

as further adjusted to give effect to the issuance and sale of senior note units in the concurrent offering, after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us, the application of the net proceeds therefrom as described above under the heading “Use of Proceeds” and the repayment of $5.1 million in outstanding long-term debt obligations owed to TriplePoint.

The following table should be read in conjunction with our consolidated financial statements and related notes, which are incorporated by reference into this prospectus supplement (unaudited):


	September 30, 2013
	Actual			As Adjusted	As Further Adjusted
Cash and cash equivalents	$	25,661,000		$	$
Debt:
2013 Notes		—
2012 Notes, net of changes in fair value of embedded derivative and debt discount		14,815,000
Secured debt, net of debt discounts		17,909,000		$	$

Total debt	$	32,724,000
Stockholders’ equity:
Common stock, $0.01 par value per share; 150,000,000 shares authorized; 47,184,896 issued and outstanding, actual; 150,000,000 shares authorized, shares issued and outstanding, as adjusted	$	472,000
Additional paid-in capital		309,115,000
Accumulated deficit		(244,824,000	)

Total stockholders’ equity	$	64,763,000		$	$

Total capitalization	$	97,487,000		$	$

The as adjusted number of shares of our common stock is based on 47,184,896 shares of common stock outstanding as of September 30, 2013 and excludes the following, measured as of November 30, 2013 (the most recent practicable date):

•

2,933,706 shares of common stock issuable upon the exercise of outstanding stock options at a weighted average exercise price of $5.19 per share;

•

1,239,998 shares of common stock issuable upon the exercise of outstanding common stock warrants at a weighted average price of $4.57 per share;

•

3,199,640 shares of common stock available for future grant under the 2010 Plan;

•

1,205,568 shares of common stock available for issuance pursuant to our Employee Stock Purchase Plan;

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•

9,562,807 shares of common stock issuable upon conversion of the outstanding 2012 Notes, at the conversion rate in effect on November 30, 2013 (which amount includes 4,837,293 shares of common stock issuable in full satisfaction of the Coupon Make-Whole Payments due in connection therewith);

•

shares of common stock issuable upon the exercise of the warrants offered hereby; and

•

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DILUTION

Our net tangible book value on September 30, 2013 was approximately $63.5 million, or approximately $1.35 per share of common stock. Net tangible book value per share is determined by dividing our net tangible book value, which consists of tangible assets less total liabilities, by the number of shares of common stock outstanding on that date. For the purpose of this calculation, the entire purchase price for the common stock units is being allocated to the shares of common stock, and the shares issuable upon exercise of the accompanying warrants have not been included. Without taking into account any other changes in the net tangible book value after September 30, 2013, other than to give effect to our receipt of the estimated net proceeds from the sale of common stock units at an offering price of $ per unit, less the underwriting fees and our estimated offering expenses, our pro forma net tangible book value as of September 30, 2013, would have been approximately $ million, or $ per share. This represents an immediate increase in the net tangible book value of $ per share to existing stockholders and an immediate dilution of $ per share to new investors in the offering. The following table illustrates this per share dilution:


Offering price per unit	$
Net tangible book value per share as of September 30, 2013	$	1.35
Increase in net tangible book value per share attributable to the offering	$
Pro forma net tangible book value per share as of September 30, 2013, after giving effect to the offering	$	—
Dilution per share to new investors in the offering	$

The information above assumes that the underwriter does not exercise its option to purchase additional shares of common stock or warrants. If the underwriter exercises in full its option to purchase additional shares of common stock and warrants, our pro forma net tangible book value per share at September 30, 2013, after giving effect to this offering, would have been $ per share, and the dilution in pro forma net tangible book value per share to investors in this offering would have been $ per share.

The above table is based on 47,184,896 shares of common stock outstanding as of September 30, 2013 and excludes the following, measured as of November 30, 2013 (the most recent practicable date):

•

2,933,706 shares of common stock issuable upon the exercise of outstanding stock options at a weighted average exercise price of $5.19 per share;

•

1,239,998 shares of common stock issuable upon the exercise of outstanding common stock warrants at a weighted average price of $4.57 per share;

•

3,199,640 shares of common stock available for future grant under the 2010 Plan;

•

1,205,568 shares of common stock available for issuance pursuant to our Employee Stock Purchase Plan;

•

shares of common stock issuable upon the exercise of the warrants offered hereby; and

•

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To the extent that any of these options or warrants are exercised, new options or shares of restricted stock are issued under the 2010 Plan or assumed in connection with future acquisitions, or new shares of common stock are issued under our Employee Stock Purchase Plan, and to the extent that some or all of the Convertible Notes are converted into shares of common stock, there will be further dilution to new investors. In addition to the current offering of shares of our common stock, we may obtain additional funds through public or private debt or equity financings in the near future. If we issue additional shares of common stock or instruments convertible into common stock, there will be further dilution to new investors.

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DESCRIPTION OF OUR COMMON STOCK

The material terms and provisions of our common stock and each other class of our securities which may qualify or limit the rights and privileges of our common stock are described under the caption “Description of Capital Stock” starting on page 13 of the accompanying prospectus.

DESCRIPTION OF OUR WARRANTS

General

The following description of the warrants offered hereby is a summary. It summarizes only those aspects of the warrants that we believe will be most important to your decision to invest in the warrants. You should keep in mind, however, that it is the terms in the warrant, and not this summary that define your rights as a holder of the warrants. There may be other provisions in the warrant that are also important to you. You should read the form of warrant for a full description of the terms of the warrants.

The warrants will be issued pursuant to one or more warrant agreements executed by us. Each warrant entitles the holder thereof to purchase of a share of our common stock at an exercise price equal to $ per share. The warrants will be exercisable during the period commencing from the date of original issuance and ending on December , 2018, the expiration date of the warrants. The warrants may be exercised by surrendering to the warrant agent the warrant certificate evidencing the warrants to be exercised with the accompanying exercise notice, appropriately completed, duly signed and delivered, together with cash payment of the exercise price, if applicable.

Upon surrender of the warrant certificate, with the exercise notice appropriately completed and duly signed and cash payment of the exercise price, if applicable, on and subject to the terms and conditions of the warrant agreement, we will deliver or cause to be delivered, to or upon the written order of such holder, the number of whole shares of common stock to which the holder is entitled, which shares may be delivered in book-entry form. If fewer than all of the warrants evidenced by a warrant certificate are to be exercised, a new warrant certificate will be issued for the remaining number of warrants.

If, and only if, a registration statement relating to the issuance of the shares underlying the warrants is not then effective or available, a holder of warrants may exercise the warrants on a cashless basis, where the holder receives the net value of the warrant in shares of common stock. However, if an effective registration statement is available for the issuance of the shares underlying the warrants, a holder may only exercise the warrants through a cash exercise. Holders of warrants will only be able to exercise their warrants if the shares of common stock underlying the warrant are qualified for sale or are at the time exempt from qualification under the applicable securities or blue sky laws of the states in which such holders (or other persons to whom it is proposed that shares be issued on exercise of the warrants) reside. Shares issued pursuant to a cashless exercise would be freely tradable without restriction or further registration under the Securities Act by persons other than our affiliates (within the meaning of Rule 144 under the Securities Act).

The exercise price and the number and type of securities purchasable upon exercise of warrants are subject to adjustment upon certain corporate events, including certain combinations, consolidations, liquidations, mergers, recapitalizations, reclassifications, reorganizations, stock dividends and stock splits, a sale of all or substantially all of our assets and certain other events.

In the event of an extraordinary transaction, as described in the warrants and generally including any merger with or into another entity, sale of all or substantially all of our assets, tender offer or exchange offer, or reclassification of our common stock, we or any successor entity will pay at the holder’s option,

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exercisable at any time concurrently with or within 30 days after the consummation of the extraordinary transaction, an amount of cash equal to the value of the warrant as determined in accordance with the Black Scholes option pricing model and the terms of the warrants.

The warrants contain weighted average anti-dilution protection upon the issuance of any common stock, securities convertible into common stock or certain other issuances at a price below the then-existing exercise price of the warrants, with certain exceptions. The terms of the warrants, including these anti-dilution protections, may make it difficult for us to raise additional capital at prevailing market terms in the future.

No fractional shares will be issued upon exercise of the warrants. The warrants do not confer upon holders any voting or other rights as stockholders of the Company.

Ownership Limitation

Notwithstanding any other provision of this description of our warrants and the warrant agreement, any exercise notice with respect to the warrants delivered by a holder will be deemed automatically not to have been so delivered by such holder to the extent, but only to the extent, that delivery of shares of our common stock or any other security otherwise deliverable upon such exercise would result in such holder having Beneficial Ownership of our common stock or any other Class in excess of the 19.999% Ownership Limitation. Any purported delivery to any holder shall be void and have no effect to the extent, but only to the extent, that after such delivery, such holder would have Beneficial Ownership of our common stock or any such Class in excess of the 19.999% Ownership Limitation.

Notwithstanding the foregoing, during any period of time in which a holder’s Beneficial Ownership of our common stock or any other Class is less than 10%, any exercise notice with respect to the warrants delivered by a holder will be deemed automatically not to have been so delivered by such holder to the extent, but only to the extent, that delivery of shares of our common stock or any other security otherwise deliverable upon such exercise would result in such holder having a Beneficial Ownership of our common stock or any other Class in excess of the 9.999% Ownership Limitation. Any purported delivery to any holder shall be void and have no effect to the extent, but only to the extent, that after such delivery, such holder would have Beneficial Ownership of our common stock or any such Class in excess of the 9.999% Ownership Limitation.

Notwithstanding the foregoing, during any period of time in which a holder’s Beneficial Ownership of our common stock or any other Class is less than 5%, any exercise notice with respect to the warrants delivered by a holder will be deemed automatically not to have been so delivered by such holder to the extent, but only to the extent, that delivery of shares of our common stock or any other security otherwise deliverable upon such exercise would result in such holder having a Beneficial Ownership of our common stock or any Class in excess of the 4.999% Ownership Limitation. Any purported delivery to any holder whose Beneficial Ownership of our common stock or any other Class is less than 5% shall be void and have no effect to the extent, but only to the extent, that after such delivery, such holder would have Beneficial Ownership of our common stock or any such Class in excess of the 4.999% Ownership Limitation.

For purposes of calculating Beneficial Ownership for each of the immediately three preceding paragraphs, the aggregate number of shares of our common stock beneficially owned by a holder will include the number of shares of our common stock issuable upon exercise of the warrants with respect to which the determination of such sentence is being made, but shall exclude the number of shares of our common stock which are issuable upon (i) exercise of the remaining, unexercised warrants beneficially owned by such holder, and (ii) exercise or conversion of the unexercised or unconverted portion of any of our other securities beneficially owned by such holder (including, without limitation, any convertible

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notes, convertible stock or warrants) that are subject to a limitation on conversion or exercise analogous to the limitation contained herein.

By written notice to us, a holder may from time to time increase or decrease either or both of the 9.999% Ownership Limitation or the 4.999% Ownership Limitation to any other percentage not in excess of the 19.999% Ownership Limitation; provided that any such increase will not be effective until the 65th day after such notice is delivered to us.

These ownership limitations will be construed, corrected and implemented in a manner so as to effectuate the intended beneficial ownership limitations herein contained and the shares of our common stock underlying the warrants in excess of the 19.999% Ownership Limitation, 9.999% Ownership Limitation or the 4.999% Ownership Limitation will not be deemed to be beneficially owned by a holder for any purpose including for purposes of Section 13(d) or Rule 16a-1(a)(1) of the Exchange Act.

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MATERIAL UNITED STATES FEDERAL INCOME TAX CONSEQUENCES

The following is a summary of the material U.S. federal income tax consequences arising from and relating to the acquisition, ownership and disposition of shares of common stock acquired as part of the common stock units, the acquisition, exercise, disposition, and lapse of warrants acquired as part of the common stock units, and the acquisition, ownership and disposition of shares of common stock received on the exercise of the warrants (the “warrant shares”).

Scope of this Summary

This summary is for general information purposes only and does not purport to be a complete analysis or listing of all potential U.S. federal income tax consequences related to the acquisition, ownership and disposition of shares of common stock, warrants and warrant shares. Except as specifically set forth below, this summary does not discuss applicable tax reporting requirements. In addition, this summary does not take into account the individual facts and circumstances of any particular holder that may affect the U.S. federal income tax consequences to such holder.

Accordingly, this summary is not intended to be, and should not be construed as, legal or U.S. federal income tax advice with respect to any particular holder. Each holder should consult its own tax advisors regarding the U.S. federal, state and local, and non-U.S. tax consequences related to the acquisition, ownership and disposition of shares of common stock, warrants and warrant shares.

No legal opinion from U.S. legal counsel or ruling from the Internal Revenue Service (the “IRS”) has been requested, or will be obtained, regarding the U.S. federal income tax consequences related to the acquisition, ownership and disposition of shares of common stock, warrants and warrant shares. This summary is not binding on the IRS, and the IRS is not precluded from taking a position that is different from, and contrary to, the positions taken in this summary.

Authorities

This summary is based upon provisions of the Internal Revenue Code of 1986, as amended (the “Code”), regulations, rulings and judicial decisions as of the date hereof. Those authorities may be changed, perhaps retroactively, or be subject to differing interpretations, so as to result in U.S. federal tax considerations different from those summarized below.

U.S. Holders

As used in this summary, the term “U.S. Holder” means a beneficial owner of shares of common stock, warrants and warrant shares acquired pursuant to this prospectus that is, for U.S. federal income tax purposes:

•

an individual who is a citizen or resident of the U.S.;

•

a corporation (or other entity taxable as a corporation) organized under the laws of the U.S., any state thereof or the District of Columbia;

•

an estate whose income is subject to U.S. federal income taxation regardless of its source; or

•

a trust that (1) is subject to the primary supervision of a court within the U.S. and the control of one or more U.S. persons for all substantial decisions or (2) has a valid election in effect under applicable Treasury Regulations to be treated as a U.S. person.

Non-U.S. Holders

For purposes of this summary, a “Non-U.S. holder” means a beneficial owner of shares of common stock, warrants, and warrant shares acquired pursuant to this prospectus that is neither a U.S. Holder

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nor a partnership (or an entity or arrangement treated as a partnership for U.S. federal income tax purposes). A Non-U.S. Holder should review the discussion under the heading “Non-U.S. Holders” below for more information.

Holders Subject to Special U.S. Federal Income Tax Rules

This summary deals only with persons or entities who hold shares of common stock, warrants or warrant shares as a capital asset within the meaning of Section 1221 of the Code (generally, property held for investment purposes). This summary does not address all aspects of U.S. federal income taxation that may be applicable to holders in light of their particular circumstances or to holders subject to special treatment under U.S. federal income tax law, such as: banks, insurance companies, and other financial institutions; dealers or traders in securities, commodities or foreign currencies; regulated investment companies; U.S. expatriates or former long-term residents of the U.S.; persons holding shares of common stock, warrants or warrant shares as part of a straddle, appreciated financial position, synthetic security, hedge, conversion transaction or other integrated investment; persons holding shares of common stock, warrants or warrant shares as a result of a constructive sale; entities that acquire shares of common stock, warrants and warrant shares that are treated as partnerships for U.S. federal income tax purposes and partners in such partnerships; real estate investment trusts; U.S. Holders that have a “functional currency” other than the U.S. dollar; holders that acquired shares of common stock, warrants, or warrant shares in connection with the exercise of employee stock options or otherwise as consideration for services; or holders that are “controlled foreign corporations” or “passive foreign investment companies.” Holders that are subject to special provisions under the Code, including holders described immediately above, should consult their own tax advisors regarding the U.S. federal, state and local, and non-U.S. tax consequences arising from and relating to the acquisition, ownership and disposition of shares of common stock, warrants and warrant shares.

If an entity classified as a partnership for U.S. federal income tax purposes holds shares of common stock, warrants or warrant shares, the tax treatment of a partner will generally depend on the status of the partner and the activities of the partnership. This summary does not address the tax consequences to any such owner or entity. Partners of entities or arrangements that are classified as partnerships for U.S. federal income tax purposes should consult their own tax advisors regarding the U.S. federal income tax consequences arising from and relating to the acquisition, ownership and disposition of shares of common stock, warrants and warrant shares.

Tax Consequences Not Addressed

This summary does not address the U.S. state and local, U.S. federal estate and gift, U.S. federal alternative minimum tax, or non-U.S. tax consequences to holders of the acquisition, ownership and disposition of shares of common stock, warrants and warrant shares. Each holder should consult its own tax advisors regarding the U.S. state and local, U.S. federal estate and gift, U.S. federal alternative minimum tax, and non-U.S. tax consequences of the acquisition, ownership and disposition of shares of common stock, warrants and warrant shares.

Characterization of the Units

For U.S. federal income tax purposes, the purchase by U.S. Holders and Non-U.S. Holders of common stock and warrants combined as a unit under this prospectus will be treated as the purchase of two components: a component consisting of one share and a component consisting of one, or a portion of one, warrant. The purchase price for each unit will be allocated between these two components in proportion to their relative fair market values at the time the unit is purchased. This allocation of the purchase price for each unit will establish the holder’s initial tax basis for U.S. federal income tax purposes in the share and one, or part of one, warrant that comprise each unit.

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For this purpose, we will allocate part of the purchase price for the unit to the share and part of the purchase price for each unit to the warrant, or part of a warrant, which comprises a unit. This allocation will be based upon our determination of the relative values of the warrants and of our common stock, which we will complete following the closing of the offering. This allocation is binding on you unless you explicitly disclose in a statement attached to your timely filed U.S. federal income tax return for the tax year that includes your acquisition date of the unit that your allocation of the purchase price is different than our allocation. However, the IRS will not be bound by our allocation of the purchase price for such units, and therefore, the IRS or a U.S. court may not respect our allocation. Each holder should consult its own tax advisor regarding the allocation of the purchase price for the units.

U.S. Holders

Exercise of Warrants

A U.S. Holder generally will not recognize gain or loss on the exercise of a warrant and related receipt of a warrant share (unless cash is received in lieu of the issuance of a fractional warrant share). A U.S. Holder’s initial tax basis in the warrant share received on the exercise of a warrant should be equal to the sum of (i) the U.S. Holder’s tax basis in the warrant plus (ii) the exercise price paid by the U.S. Holder on the exercise of the warrant. A U.S. Holder’s holding period for the warrant share received on the exercise of a warrant will begin on the day after the warrant is exercised by the U.S. Holder.

The U.S. federal income tax treatment of a cashless exercise of warrants into warrant shares is unclear, and the tax consequences of a cashless exercise could differ from the consequences upon the exercise of a warrant described in the preceding paragraph. U.S. Holders should consult their own tax advisors regarding the U.S. federal income tax consequences of a cashless exercise of warrants.

Disposition of Warrants

A U.S. Holder will recognize gain or loss on the sale or other taxable disposition of a warrant in an amount equal to the difference, if any, between (i) the amount of cash plus the fair market value of any property received upon such taxable disposition and (ii) the U.S. Holder’s tax basis in the warrant sold or otherwise disposed of. Any such gain or loss generally will be a capital gain or loss, which will be long-term capital gain or loss if the warrant is held for more than one year. Long-term capital gains recognized by certain non-corporate U.S. Holders (including individuals) may be eligible for preferential rates of taxation. Deductions for capital losses are subject to limitations under the Code.

Expiration of Warrants without Exercise

Upon the lapse or expiration of a warrant, a U.S. Holder will recognize a loss in an amount equal to such U.S. Holder’s tax basis in the warrant. Any such loss generally will be a capital loss and will be long-term capital loss if the warrant is held for more than one year. Deductions for capital losses are subject to limitations under the Code.

Certain Adjustments to the Warrants

Under Section 305 of the Code, an adjustment to the number of warrant shares that will be issued on the exercise of the warrants, or an adjustment to the exercise price of the warrants, may be treated as a constructive distribution to a U.S. Holder of the warrants if, and to the extent that, such adjustment has the effect of increasing such U.S. Holder’s proportionate interest in our “earnings and profits” or assets, depending on the circumstances of such adjustment (for example, if such adjustment is to compensate for a distribution of cash or other property to our stockholders). Adjustments to the exercise price of a warrant made pursuant to a bona fide reasonable adjustment formula that has the effect of preventing dilution of the interest of the holders of the warrants should generally not result in a constructive

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distribution. (See the more detailed discussion of the rules applicable to distributions made by us at “Distributions on Shares of Common Stock and Warrant Shares” below).

Distributions on Shares of Common Stock and Warrant Shares

We have never declared or paid any cash dividends on our common stock and do not anticipate paying any cash dividends on our common stock in the foreseeable future. If we were to pay cash dividends in the future, such distributions made on shares of common stock and warrant shares generally would be included in a U.S. Holder’s income as ordinary dividend income to the extent of our current and accumulated earnings and profits (determined under U.S. federal income tax principles) as of the end of our taxable year in which the distribution occurred. Dividends received by certain non-corporate U.S. Holders may be eligible for taxation at preferential rates provided certain holding period and other requirements are satisfied. Distributions in excess of our current and accumulated earnings and profits will be treated as a return of capital to the extent of a U.S. Holder’s adjusted tax basis in the shares and thereafter as capital gain from the sale or exchange of such shares, which will be taxable according to rules discussed under the heading “Sale, Certain Redemptions or Other Taxable Dispositions of Shares of Common Stock and Warrant Shares,” below. Dividends received by a corporate holder may be eligible for a dividends received deduction, subject to applicable limitations.

Sale, Certain Redemptions or Other Taxable Dispositions of Shares of Common Stock and Warrant Shares

Upon the sale, certain qualifying redemptions, or other taxable disposition of shares of common stock or warrant shares, a U.S. Holder generally will recognize capital gain or loss equal to the difference, if any, between (i) the amount of cash and the fair market value of any property received upon such taxable disposition and (ii) the U.S. Holder’s adjusted tax basis in the shares of common stock or warrant shares sold or otherwise disposed of. Such capital gain or loss will be long-term capital gain or loss if a U.S. Holder’s holding period in the shares of common stock or warrant shares is more than one year at the time of the taxable disposition. Long-term capital gains recognized by certain non-corporate U.S. Holders (including individuals) may be eligible for taxation at preferential rates. Deductions for capital losses are subject to limitations under the Code.

Additional Tax on Passive Income

Individuals, estates and certain trusts whose income exceeds certain thresholds will be required to pay a 3.8% Medicare surtax on “net investment income” including, among other things, dividends and net gain from disposition of property (other than property held in certain trades or businesses). U.S. Holders should consult their own tax advisors regarding the effect, if any, of this tax on their ownership and disposition of shares of common stock, warrants and warrant shares.

Information Reporting and Backup Withholding

Information reporting requirements generally will apply to payments of dividends on shares of common stock and warrant shares and to the proceeds of a sale of shares of common stock, warrants or warrant shares paid to a U.S. Holder unless the U.S. Holder is an exempt recipient (such as a corporation). Backup withholding will apply to those payments if the U.S. Holder fails to provide its correct taxpayer identification number, or certification of exempt status, or if the U.S. Holder is notified by the IRS that it has failed to report in full payments of interest and dividend income. Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules generally will be allowed as a refund or a credit against a U.S. Holder’s U.S. federal income tax liability, if any, provided the required information is furnished in a timely manner to the IRS.

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Non-U.S. Holders

Exercise of Warrants

A Non-U.S. Holder generally will not recognize gain or loss for U.S. tax purposes on the exercise of a warrant and related receipt of a warrant share (unless cash is received in lieu of the issuance of a fractional warrant share and certain other conditions are present, as discussed below under “Sale or Other Taxable Disposition of Shares of Common Stock, Warrants and Warrant Shares”).

The U.S. federal income tax treatment of a cashless exercise of warrants into warrant shares is unclear, and the tax consequences of a cashless exercise could differ from the consequences upon the exercise of a warrant described in the preceding paragraph. Non-U.S. Holders should consult their own tax advisors regarding the U.S. federal income tax consequences of a cashless exercise of warrants.

Expiration of Warrants without Exercise

Upon the lapse or expiration of a warrant, a Non-U.S. Holder will not recognize a capital loss unless such U.S. Holder is otherwise subject to U.S. federal income tax.

Certain Adjustments to the Warrants

Under Section 305 of the Code, an adjustment to the number of warrant shares that will be issued on the exercise of the warrants, or an adjustment to the exercise price of the warrants, may be treated as a constructive distribution to a Non-U.S. Holder of the warrants if, and to the extent that, such adjustment has the effect of increasing such Non-U.S. Holder’s proportionate interest in our “earnings and profits” or assets, depending on the circumstances of such adjustment (for example, if such adjustment is to compensate for a distribution of cash or other property to our stockholders). Adjustments to the exercise price of a warrant made pursuant to a bona fide reasonable adjustment formula that has the effect of preventing dilution of the interest of the holders of the warrants should generally not result in a constructive distribution. See the more detailed discussion of the rules applicable to distributions made by us under the heading “Distributions on Shares of Common Stock and Warrant Shares” below.

Distributions on Shares of Common Stock and Warrant Shares

Cash distributions on shares of common stock and warrant shares generally will constitute dividends for U.S. federal income tax purposes to the extent paid out of our current or accumulated earnings and profits, as determined under U.S. federal income tax principles. Distributions in excess of current and accumulated earnings and profits will be applied against and reduce a Non-U.S. Holder’s tax basis in shares of common stock or warrant shares, to the extent thereof, and any excess will be treated as capital gain realized on the sale or other disposition of the shares and subject to tax in the manner described under the heading “Sale or Other Taxable Disposition of Shares of Common Stock, Warrants and Warrant Shares,” below.

Any dividends paid to a Non-U.S. Holder with respect to shares of common stock or warrant shares that constitute dividends under the rules described above generally will be subject to withholding of U.S. federal income tax at a 30% rate or such lower rate as may be specified by an applicable income tax treaty. However, dividends that are effectively connected with the conduct of a trade or business by a Non-U.S. Holder within the U.S. and, where an income tax treaty applies, are attributable to a U.S. permanent establishment of the Non-U.S. Holder, are not subject to this withholding tax, but

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instead are subject to U.S. federal income tax on a net income basis at applicable individual or corporate rates. A Non-U.S. Holder generally must deliver an IRS Form W-8ECI certifying under penalties of perjury that such dividends are effectively connected with a U.S. trade or business of the holder in order for effectively connected dividends to be exempt from this withholding tax. Any such effectively connected dividends received by a foreign corporation may be subject to an additional “branch profits tax” at a 30% rate or such lower rate as may be specified by an applicable income tax treaty.

A Non-U.S. Holder of shares of common stock or warrant shares who is entitled to and wishes to claim the benefits of an applicable treaty rate (and avoid backup withholding as discussed below) with respect to dividends received generally will be required to (i) complete an IRS Form W-8BEN (or an acceptable substitute form) and make certain certifications, under penalty of perjury, to establish its status as a non-U.S. person and its entitlement to treaty benefits or (ii) if the stock is held through certain foreign intermediaries, satisfy the relevant certification requirements of applicable U.S. Treasury regulations. Special certification and other requirements apply to certain Non-U.S. Holders that are entities rather than individuals.

The certification requirements described above must be satisfied prior to the payment of dividends and may be required to be updated periodically. A Non-U.S. Holder eligible for a reduced rate of U.S. federal withholding tax pursuant to an income tax treaty may obtain a refund of any excess amounts withheld by timely filing an appropriate claim for refund with the IRS.

Sale or Other Taxable Disposition of Shares of Common Stock, Warrants and Warrant Shares

In general, a Non-U.S. Holder of shares of common stock, warrants or warrant shares will not be subject to U.S. federal income tax with respect to gain recognized on a sale or other disposition of such shares of common stock, warrants or warrant shares, unless: (i) the gain is effectively connected with a trade or business of the Non-U.S. Holder in the U.S. and, where a tax treaty applies, is attributable to a U.S. permanent establishment of the Non-U.S. Holder (in which case, the special rules described below apply), (ii) in the case of a Non-U.S. Holder who is an individual, such holder is present in the U.S. for 183 or more days in the taxable year of the sale or other disposition and certain other conditions are met, in which case the gain would be subject to a flat 30% tax, or such reduced rate as may be specified by an applicable income tax treaty, which may be offset by U.S. source capital losses, even though the individual is not considered a resident of the U.S.; or (iii) subject to certain exceptions, we are or have been a “U.S. real property holding corporation,” as such term is defined in Section 897(c) of the Code, during the shorter of the five-year period ending on the date of disposition or the holder’s holding period of our shares of common stock, warrants or warrant shares.

We believe we currently are not, and do not anticipate becoming, a “U.S. real property holding corporation” for U.S. federal income tax purposes.

Any gain described in (i) above will be subject to U.S. federal income tax at the regular graduated rates. If the Non-U.S. Holder is a corporation, under certain circumstances, that portion of its earnings and profits that is effectively connected with its U.S. trade or business, subject to certain adjustments, generally would be subject to a “branch profits tax.” The branch profits tax rate is generally 30%, although an applicable income tax treaty between the U.S. and the Non-U.S. Holder’s country of residence might provide for a lower rate.

Information Reporting and Backup Withholding

We must report annually to the IRS and to each Non-U.S. Holder the amount of dividends paid to such holder on the shares of common stock and warrant shares and the tax withheld (if any) with respect to such dividends, regardless of whether withholding was required. Copies of the information returns reporting such dividends and any withholding may also be made available to the tax authorities in the

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country in which the Non-U.S. Holder resides under the provisions of an applicable income tax treaty or information sharing agreement. In addition, dividends paid to a Non-U.S. Holder may be subject to backup withholding unless applicable certification requirements are met.

Payment of the proceeds of a sale of shares of common stock or warrant shares within the U.S. or conducted through certain U.S. related financial intermediaries is subject to information reporting and, depending upon the circumstances, backup withholding unless the Non-U.S. Holder certifies under penalties of perjury that it is not a U.S. person (and the payor does not have actual knowledge or reason to know that the holder is a U.S. person) or the holder otherwise establishes an exemption.

Any amounts withheld under the backup withholding rules may be allowed as a refund or a credit against such holder’s U.S. federal income tax liability provided the required information is timely furnished to the IRS.

Legislation Affecting Taxation of Common Stock Held By or Through Foreign Entities (“FATCA”)

Recent legislation, commonly referred to as FATCA, may impose a withholding tax on certain payments to foreign entities. FATCA generally would impose a 30% withholding tax on dividends on shares of common stock and warrant shares, or gross proceeds from the sale or other disposition of, shares of common stock, warrants, and warrant shares paid to (i) a “foreign financial institution” unless such institution enters into an agreement with the U.S. Treasury, or complies with its obligations pursuant to an intergovernmental agreement between the U.S. and the jurisdiction in which the institution is resident, to among other things, undertake to identify accounts held by certain U.S. persons or U.S.-owned foreign entities, annually report certain information about such accounts, and to the extent required, withhold 30% on payments to account holders whose actions prevent it from complying with these reporting and other requirements, and (ii) a non-financial foreign entity unless such entity provides the withholding agent with a certification that it does not have any substantial U.S. owners or a certification identifying the direct and indirect substantial U.S. owners of the entity. Under recently issued U.S. Treasury regulations and IRS guidance, FATCA withholding generally would only apply to payments of dividends made after June 30, 2014, and payments of gross proceeds from the disposition of stock made after December 31, 2016. Under certain circumstances, a holder may be eligible for refunds or credits of such withholding taxes. Investors are urged to consult with their own tax advisors regarding the possible application of these rules to their investment in our common stock, warrants, and warrant shares.

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UNDERWRITING

We are offering common stock units as described in this prospectus supplement and the accompanying prospectus through Piper Jaffray & Co., the sole manager of this offering. We have entered into an underwriting agreement with the underwriter.

The underwriting agreement provides that the underwriter must buy all of the common stock units if it buys any of them. However, the underwriter is not required to take or pay for the common stock or warrants covered by the underwriter’s over-allotment option described below.

Our common stock units are offered subject to a number of conditions, including:

•

receipt and acceptance of our common stock units by the underwriter; and

•

the underwriter’s right to reject orders in whole or in part.

In connection with this offering, the underwriter or securities dealers may distribute prospectuses electronically.

Concurrently with this offering of common stock units, we are offering senior note units, with each senior note unit consisting of $1,000 principal amount of 2013 Notes and warrants to purchase shares of our common stock (or a total of $ aggregate principal amount of 2013 Notes and warrants to purchase up to shares of our common stock if the underwriter for the concurrent offering of senior note units exercises in full its option to purchase such additional securities) (and the common stock issuable from time to time upon exercise of each of the warrants) pursuant to a separate prospectus supplement. This offering of common stock units is not contingent upon the concurrent offering of senior note units, and the concurrent offering of senior note units is not contingent upon this offering of common stock units. The 2013 Notes will be convertible into shares of our common stock in accordance with the terms thereof and the indenture under which they are issued. The warrants offered in the concurrent offering of senior note units are expected to have a materially higher exercise price compared to the warrants offered hereby, but are otherwise expected to be substantially similar.

Over-Allotment Option

We have granted the underwriter an over-allotment option. This option, which is exercisable for up to 30 days after the date of this prospectus supplement, permits the underwriter to purchase up to additional shares of common stock and/or warrants to purchase up to shares of common stock at a price per share of $ and at a price per warrant of $ , to cover over-allotments, if any.

Commissions and Discounts

Common stock units sold by the underwriter to the public will initially be offered at the public offering price set forth on the cover of this prospectus supplement. Sales of common stock units made outside the U.S. may be made by affiliates of the underwriter. If all the common stock units are not sold at the public offering price, the underwriter may change the offering price and the other selling terms. Upon execution of the underwriting agreement, the underwriter will be obligated to purchase the common stock units at the prices and upon the terms stated therein.

The following table shows the per unit and total underwriting discounts and commissions we will pay to the underwriter assuming both no exercise and full exercise of the underwriter’s option to purchase additional common stock and warrants.


	No exercise	Full exercise
Per Unit
Total

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We estimate that the total expenses of this offering payable by us, not including the underwriting discounts and commissions, will be approximately $ ; which includes the payment of certain legal fees incurred by Total Energy Ventures International in connection with this offering and $150,000 that we have agreed to reimburse to the underwriter for expenses incurred by it in connection with this offering and the concurrent offering of senior note units. In accordance with FINRA Rule 5110, the amount reimbursed to the underwriter is deemed underwriter compensation for this offering.

Determination of Offering Price

The public offering price of the common stock units and the exercise price and other terms of the warrants were negotiated between us and the underwriter, based on the trading price of our common stock prior to the offering, among other things. Other factors considered in determining the public offering price of the common stock units we are offering and the exercise price and other terms of the warrants include the history and prospects of the Company, the stage of development of our business, our business plans for the future and the extent to which they have been implemented, an assessment of our management, general conditions of the securities markets at the time of the offering and such other factors as were deemed relevant.

No Sales of Similar Securities

We, and our executive officers and directors, have entered into lock-up agreements with the underwriter. Under these agreements, we and each of these persons may not, without the prior written approval of Piper Jaffray & Co., offer, sell, contract to sell, pledge, or otherwise dispose of, directly or indirectly, or hedge our common stock, any debt securities of the Company or any other securities of the Company that are substantially similar to our common stock or the 2013 Notes, or securities convertible into or exchangeable or exercisable for our common stock, except in the circumstances described below. These restrictions will be in effect for a period of 90 days after the date of this prospectus supplement, which period is subject to extension in the circumstances described below. At any time and without public notice, Piper Jaffray & Co. may, in its sole discretion, release some or all of the securities from these lock-up agreements.

The restrictions set forth above are subject to customary exceptions and, in addition to such customary exceptions, shall not apply to:

•

the issuance by us of the common stock and warrants being offered hereby and the issuance by us of common stock upon the exercise of such warrants;

•

the issuance by us of 2013 Notes and warrants in the concurrent offering of senior note units and of shares of common stock issuable upon conversion of the Convertible Notes, including the issuance of common stock in full satisfaction of any Coupon Make-Whole Payments due in connection therewith, and the shares of common stock issuable upon exercise of the accompanying warrants;

•

the issuance by us of common stock upon the exercise of warrants held by TriplePoint that have had their exercise price adjusted in connection with the issuance of the 2013 Notes;

•

our registration under the Securities Act or the issuance and sale by us of shares of our common stock to one or more counterparties in connection with any strategic partnership, joint venture, collaboration, lending or other similar arrangement, or in connection with the acquisition or license by the Company or any of its subsidiaries of any business, products, facilities, or intellectual property as long as (i) the number of shares issued does not exceed 15% of the number of shares of our common stock outstanding immediately after this offering and (ii) each of the recipients of these shares executes a lock-up agreement for the remainder of the lock-up period;

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•

transfers by our executive officers and directors in connection with the receipt or vesting of securities issued by us pursuant to any equity incentive or other compensatory plans, including the withholding by us or the surrender of such securities and/or any sale or other disposition of such securities, solely in order to satisfy tax liabilities with respect to such issuance or vesting or any deemed disposition or deemed sale with respect to such securities; or

•

transfers by our executive officers and directors pursuant to existing trading plans pursuant to Rule 10b5-1 under the Exchange Act.

In the event that either:

•

during the last 15 calendar days plus three business days of the 90-day restricted period, we issue an earnings release or material news or a material event relating to us occurs, or

•

prior to the expiration of the 90-day restricted period, we announce that we will release earnings results during the 16-day period beginning on the last day of the 90-day restricted period,

the expiration of the 90-day restricted period will be extended until the expiration of the 15 calendar day plus three business day period beginning on the date of the issuance of an earnings release or the occurrence of the material news or event, as applicable, unless the underwriter waives such extension.

Indemnification

We have agreed to indemnify the underwriter against certain liabilities, including certain liabilities under the Securities Act. If we are unable to provide this indemnification, we have agreed to contribute to payments the underwriter may be required to make in respect of those liabilities.

NASDAQ Stock Market Listing

Our common stock is listed on the NASDAQ Global Market under the symbol “GEVO.” The warrants are not and will not be listed for trading on the NASDAQ Global Market, or any other securities exchange.

Price Stabilization, Short Positions

In connection with this offering, the underwriter may engage in activities that stabilize, maintain or otherwise affect the price of our common stock, including:

•

stabilizing transactions;

•

short sales;

•

purchases to cover positions created by short sales;

•

imposition of penalty bids; and

•

syndicate covering transactions.

Stabilizing transactions consist of bids or purchases made for the purpose of preventing or retarding a decline in the market price of our common stock while this offering is in progress. These transactions may also include making short sales of our common stock, which involve the sale by the underwriter of a greater number of shares of our common stock than they are required to purchase in this offering, and purchasing shares of our common stock on the open market to cover positions created by short sales. Short sales may be “covered short sales,” which are short positions in an amount not greater than the underwriter’s over-allotment option referred to above, or may be “naked short sales,” which are short positions in excess of that amount.

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The underwriter may close out any covered short position by either exercising their over-allotment option, in whole or in part, or by purchasing shares in the open market. In making this determination, the underwriter will consider, among other things, the price of shares available for purchase in the open market as compared to the price at which it may purchase shares through the over-allotment option.

Naked short sales are short sales made in excess of the over-allotment option. The underwriter must close out any naked short position by purchasing shares in the open market. A naked short position is more likely to be created if the underwriter is concerned that there may be downward pressure on the price of the common stock in the open market that could adversely affect investors who purchased in this offering.

As a result of these activities, the price of our common stock may be higher than the price that otherwise might exist in the open market. If these activities are commenced, they may be discontinued by the underwriter at any time. The underwriter may carry out these transactions on the NASDAQ Global Market, in the over-the-counter market or otherwise.

Affiliations

The underwriter and certain of its affiliates have in the past provided, are currently providing and may in the future from time to time provide, investment banking and other financing, trading, banking, research, transfer agent and trustee services to the Company, for which they have in the past received, and may currently or in the future receive, customary fees and expenses. In addition, the underwriter of this offering is also acting as the underwriter of the concurrent offering of senior note units.

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NOTICE TO INVESTORS

Notice to prospective investors in the European Economic Area

In relation to each member state of the European Economic Area (the “EEA”) that has implemented the Prospectus Directive (as defined below) (each, a “Relevant Member State”), other than Germany, with effect from and including the date on which the Prospectus Directive is implemented in that Relevant Member State, an offer of securities described in this prospectus supplement may not be made to the public in that Relevant Member State other than:

•

to any legal entity which is a qualified investor as defined in the Prospectus Directive;

•

by the underwriter to fewer than 100 or, if the Relevant Member State has implemented the relevant provisions of the 2010 PD Amending Directive (as defined below), 150, natural or legal persons (other than qualified investors as defined in the Prospectus Directive), as permitted under the Prospectus Directive, subject to obtaining the prior consent of Piper Jaffray & Co. for any such offer; or

•

in any other circumstances falling within Article 3(2) of the Prospectus Directive;

provided that no such offer of securities shall require us or any underwriter to publish a prospectus pursuant to Article 3 of the Prospectus Directive.

For purposes of this provision, the expression an “offer of securities to the public” in any Relevant Member State means the communication in any form and by any means of sufficient information on the terms of the offer and the securities to be offered so as to enable an investor to decide to purchase or subscribe for the securities, as the expression may be varied in that member state by any measure implementing the Prospectus Directive in that member state, and the expression “Prospectus Directive” means Directive 2003/71/EC (and amendments thereto, including the 2010 PD Amending Directive, to the extent implemented in the Relevant Member State), and includes any relevant implementing measure in the Relevant Member State. The expression “2010 PD Amending Directive” means Directive 2010/73/EU.

We have not authorized and do not authorize the making of any offer of securities through any financial intermediary on its behalf, other than offers made by the underwriter with a view to the final placement of the securities as contemplated in this prospectus. Accordingly, no purchaser of the securities, other than the underwriter, is authorized to make any further offer of the securities on behalf of us or the underwriter.

The EEA selling restriction is in addition to any other selling restrictions set out in this prospectus.

Notice to prospective investors in Australia

This prospectus supplement is not a formal disclosure document and has not been, nor will be, lodged with the Australian Securities and Investments Commission. It does not purport to contain all information that an investor or its professional advisers would expect to find in a prospectus or other disclosure document (as defined in the Corporations Act 2001 (Australia)) for the purposes of Part 6D.2 of the Corporations Act 2001 (Australia) or in a product disclosure statement for the purposes of Part 7.9 of the Corporations Act 2001 (Australia), in either case, in relation to the securities.

The securities are not being offered in Australia to “retail clients” as defined in Sections 761G and 761GA of the Corporations Act 2001 (Australia). This offering is being made in Australia solely to “wholesale clients” for the purposes of Section 761G of the Corporations Act 2001 (Australia) and, as

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such, no prospectus, product disclosure statement or other disclosure document in relation to the securities has been, or will be, prepared.

This prospectus supplement does not constitute an offer in Australia other than to wholesale clients. By submitting an application for our securities, you represent and warrant to us that you are a wholesale client for the purposes of Section 761G of the Corporations Act 2001 (Australia). If any recipient of this prospectus supplement is not a wholesale client, no offer of, or invitation to apply for, our securities shall be deemed to be made to such recipient and no applications for our securities will be accepted from such recipient. Any offer to a recipient in Australia, and any agreement arising from acceptance of such offer, is personal and may only be accepted by the recipient. In addition, by applying for our securities you undertake to us that, for a period of 12 months from the date of issuance of the securities, you will not transfer any interest in the securities to any person in Australia other than to a wholesale client.

Notice to prospective investors in Hong Kong

Our securities may not be offered or sold in Hong Kong, by means of this prospectus supplement or any document other than (1) to “professional investors” within the meaning of the Securities and Futures Ordinance (Cap. 571, Laws of Hong Kong) and any rules made thereunder, (2) in circumstances which do not constitute an offer to the public within the meaning of the Companies Ordinance (Cap. 32, Laws of Hong Kong), or (3) in other circumstances which do not result in the document being a “prospectus” within the meaning of the Companies Ordinance (Cap. 32, Laws of Hong Kong). No advertisement, invitation or document relating to our securities may be issued or may be in the possession of any person for the purpose of issue (in each case whether in Hong Kong or elsewhere) which is directed at, or the contents of which are likely to be accessed or read by, the public in Hong Kong (except if permitted to do so under the securities laws of Hong Kong) other than with respect to the securities which are or are intended to be disposed of only to persons outside Hong Kong or only to “professional investors” within the meaning of the Securities and Futures Ordinance (Cap. 571, Laws of Hong Kong) and any rules made thereunder.

Notice to prospective investors in Japan

Our securities have not been and will not be registered under the Financial Instruments and Exchange Law of Japan (the “Financial Instruments and Exchange Law”) and our securities will not be offered or sold, directly or indirectly, in Japan, or to, or for the benefit of, any resident of Japan (which term as used herein means any person resident in Japan, including any corporation or other entity organized under the laws of Japan), or to others for re-offering or resale, directly or indirectly, in Japan, or to a resident of Japan, except pursuant to an exemption from the registration requirements of, and otherwise in compliance with, the Financial Instruments and Exchange Law and any other applicable laws, regulations and ministerial guidelines of Japan.

Notice to prospective investors in Singapore

This document has not been registered as a prospectus with the Monetary Authority of Singapore and in Singapore, the offer and sale of our securities is made pursuant to exemptions provided in Sections 274 and 275 of the Securities and Futures Act, Chapter 289 of Singapore (the “SFA”). Accordingly, this prospectus supplement and any other document or material in connection with the offer or sale, or invitation for subscription or purchase, of our securities may not be circulated or distributed, nor may our securities be offered or sold, or be made the subject of an invitation for subscription or purchase, whether directly or indirectly, to persons in Singapore other than (1) to an institutional investor as defined in Section 4A of the SFA pursuant to Section 274 of the SFA, (2) to a relevant person as defined in Section 275(2) of the SFA pursuant to Section 275(1) of the SFA, or any person pursuant to Section 275(1A) of the SFA, and in accordance with the conditions specified in Section 275 of the SFA or (3) otherwise pursuant to, and in accordance with the conditions of, any other applicable provision of

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the SFA, in each case subject to compliance with the conditions (if any) set forth in the SFA. Moreover, this document is not a prospectus as defined in the SFA. Accordingly, statutory liability under the SFA in relation to the content of prospectuses would not apply. Prospective investors in Singapore should consider carefully whether an investment in our securities is suitable for them.

Where our securities are subscribed or purchased under Section 275 of the SFA by a relevant person, which is:

•

by a corporation (which is not an accredited investor as defined in Section 4A of the SFA), the sole business of which is to hold investments and the entire share capital of which is owned by one or more individuals, each of whom is an accredited investor; or

•

for a trust (where the trustee is not an accredited investor), whose sole purpose is to hold investments and each beneficiary of the trust is an individual who is an accredited investor;

shares of that corporation or the beneficiaries’ rights and interest (howsoever described) in that trust shall not be transferable for six months after that corporation or that trust has acquired the shares under Section 275 of the SFA, except:

•

to an institutional investor (for corporations under Section 274 of the SFA) or to a relevant person defined in Section 275(2) of the SFA, or any person pursuant to an offer that is made on terms that such shares of that corporation or such rights and interest in that trust are acquired at a consideration of not less than S$200,000 (or its equivalent in a foreign currency) for each transaction, whether such amount is to be paid for in cash or by exchange of securities or other assets, and further for corporations, in accordance with the conditions specified in Section 275 of the SFA;

•

where no consideration is given for the transfer; or

•

where the transfer is by operation of law.

In addition, investors in Singapore should note that the securities acquired by them are subject to resale and transfer restrictions specified under Section 276 of the SFA, and they, therefore, should seek their own legal advice before effecting any resale or transfer of their securities.

Notice to prospective investors in Switzerland

This prospectus supplement does not constitute an issue prospectus pursuant to Article 652a or Article 1156 of the Swiss Code of Obligations (the “CO”) and the shares will not be listed on the SIX Swiss Exchange. Therefore, this prospectus supplement may not comply with the disclosure standards of the CO and/or the listing rules (including any prospectus schemes) of the SIX Swiss Exchange. Accordingly, the shares may not be offered to the public in or from Switzerland, but only to a selected and limited circle of investors, which do not subscribe to the shares with a view to distribution.

Notice to prospective investors in the United Kingdom

This prospectus supplement is only being distributed to and is only directed at: (1) persons who are outside the United Kingdom; (2) investment professionals falling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005 (the “Order”); or (3) high net worth companies, and other persons to whom it may lawfully be communicated, falling within Article 49(2)(a) to (d) of the Order (all such persons falling within (1)-(3) together being referred to as “Relevant Persons”). The shares are only available to, and any invitation, offer or agreement to subscribe, purchase or otherwise acquire such shares will be engaged in only with, Relevant Persons. Any person who is not a Relevant Person should not act or rely on this prospectus supplement or any of its contents.

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LEGAL MATTERS

The validity of the securities being offered by this prospectus will be passed upon by our counsel, Paul Hastings LLP, San Diego, California. Goodwin Procter LLP, New York, New York is counsel for the underwriter in connection with this offering.

EXPERTS

The consolidated financial statements incorporated by reference in this prospectus supplement have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their report (which report expresses an unqualified opinion on the consolidated financial statements and includes an explanatory paragraph regarding Gevo, Inc.’s status as a development stage enterprise), which is incorporated herein by reference. Such consolidated financial statements have been so incorporated in reliance upon the report of such firm given upon their authority as experts in accounting and auditing.

WHERE YOU CAN FIND ADDITIONAL INFORMATION

We file annual, quarterly and special reports, proxy statements and other information with the SEC. You may read and copy any document we file at the SEC’s Public Reference Room at 100 F Street, N.E., Washington, DC 20549. Please call the SEC at 1-800-SEC-0330 for more information about the operation of the Public Reference Room. The SEC maintains an internet website at http://www.sec.gov that contains reports, proxy and information statements, and other information regarding issuers that file electronically with the SEC, including Gevo, Inc. You may also access our reports and proxy statements free of charge at our website, http://www.gevo.com. The information contained in, or that can be accessed through, our website is not part of this prospectus supplement. The prospectus included in this filing is part of a registration statement filed by us with the SEC. The full registration statement can be obtained from the SEC, as indicated above, or from us.

INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

The SEC allows us to incorporate by reference the information we file with it, which means that we can disclose important information to you by referring you to another document that we have filed separately with the SEC. We hereby incorporate by reference the following information or documents into this prospectus supplement and the accompanying prospectus:

•

our Annual Report on Form 10-K for the fiscal year ended December 31, 2012, filed with the SEC on March 26, 2013;

•

our Amendment No. 1 to the Annual Report on Form 10-K for the fiscal year ended December 31, 2012, filed with the SEC on April 12, 2013;

•

our Quarterly Report on Form 10-Q for the three months ended March 31, 2013, filed with the SEC on May 6, 2013;

•

our Quarterly Report on Form 10-Q for the three months ended June 30, 2013, filed with the SEC on August 14, 2013;

•

our Quarterly Report on Form 10-Q for the three months ended September 30, 2013, filed with the SEC on November 5, 2013;

•

our Current Reports on Form 8-K filed with the SEC on January 2, 2013, March 20, 2013, March 21, 2013, June 10, 2013, June 18, 2013, July 29, 2013 and September 6, 2013 (excluding any information furnished and not filed pursuant to any such Current Report); and

•

the description of our common stock contained in our Registration Statement on Form S-1 (File No. 333-168792), filed with the SEC on August 12, 2010, including any subsequent amendment or report filed for the purpose of amending such description.

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Any information in any of the foregoing documents will automatically be deemed to be modified or superseded to the extent that information in this prospectus supplement or the accompanying prospectus or in a later filed document that is incorporated or deemed to be incorporated herein by reference modifies or replaces such information.

We also incorporate by reference any future filings (other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items) made with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, until we sell all of the securities offered by this prospectus supplement. Information in such future filings updates and supplements the information provided in this prospectus supplement. Any statements in any such future filings will automatically be deemed to modify and supersede any information in any document we previously filed with the SEC that is incorporated or deemed to be incorporated herein by reference to the extent that statements in the later filed document modify or replace such earlier statements.

Upon written or oral request, we will provide to you, without charge, a copy of any or all of the documents that are incorporated by reference into this prospectus supplement and the accompanying prospectus but not delivered with the prospectus, including exhibits which are specifically incorporated by reference into such documents. Requests should be directed to: Gevo, Inc., Attention: Investor Relations, 345 Inverness Drive South, Building C, Suite 310, Englewood, Colorado 80112, telephone (303) 858-8358.

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PROSPECTUS

LOGO

$250,000,000

Common Stock

Preferred Stock

Debt Securities

Warrants

Units

From time to time, we may offer up to $250,000,000 of any combination of the securities described in this prospectus, either individually or in units. We may also offer common stock or preferred stock upon conversion of debt securities, common stock upon conversion of preferred stock, or common stock, preferred stock or debt securities upon the exercise of warrants.

We will provide the specific terms of these offerings and securities in one or more supplements to this prospectus. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings. The prospectus supplement and any related free writing prospectus may also add, update or change information contained in this prospectus. You should carefully read this prospectus, the applicable prospectus supplement and any related free writing prospectus, as well as any documents incorporated by reference, before buying any of the securities being offered.

Our common stock is traded on the NASDAQ Global Market under the symbol “GEVO”. On April 30, 2013, the last reported sale price of our common stock on the NASDAQ Global Market was $1.85. The applicable prospectus supplement will contain information, where applicable, as to any other listing, if any, on the NASDAQ Global Market or any securities market or other exchange of the securities covered by the applicable prospectus supplement.

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus.

This prospectus may not be used to consummate a sale of any securities unless accompanied by a prospectus supplement.

The securities may be sold directly by us to investors, through agents designated from time to time or to or through underwriters or dealers, on a continuous or delayed basis. For additional information on the methods of sale, you should refer to the section entitled “Plan of Distribution” in this prospectus. If any agents or underwriters are involved in the sale of any securities with respect to which this prospectus is being delivered, the names of such agents or underwriters and any applicable fees, commissions, discounts and over-allotment options will be set forth in a prospectus supplement. The price to the public of such securities and the net proceeds that we expect to receive from such sale will also be set forth in a prospectus supplement.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is May 15, 2013.

TABLE OF CONTENTS


	Page
ABOUT THIS PROSPECTUS		1
CONVENTIONS THAT APPLY TO THIS PROSPECTUS		2
GEVO, INC.		3
RISK FACTORS		5
CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS		6
THE SECURITIES WE MAY OFFER		8
RATIO OF EARNINGS TO FIXED CHARGES		11
USE OF PROCEEDS		12
DESCRIPTION OF CAPITAL STOCK		13
DESCRIPTION OF DEBT SECURITIES		16
DESCRIPTION OF WARRANTS		23
DESCRIPTION OF UNITS		25
LEGAL OWNERSHIP OF SECURITIES		27
PLAN OF DISTRIBUTION		30
LEGAL MATTERS		32
EXPERTS		32
MATERIAL CHANGES		32
WHERE YOU CAN FIND ADDITIONAL INFORMATION		33

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission (the “SEC”) utilizing a “shelf” registration process. Under this shelf registration process, we may offer shares of our common stock and preferred stock, various series of debt securities and/or warrants to purchase any of such securities, either individually or in units, in one or more offerings, up to a total dollar amount of $250,000,000. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will contain more specific information about the terms of those securities. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. We may also add or update in the prospectus supplement (and in any related free writing prospectus that we may authorize to be provided to you) any of the information contained in this prospectus or in the documents that we have incorporated by reference into this prospectus. We urge you to carefully read this prospectus, any applicable prospectus supplement and any related free writing prospectus, together with the information incorporated herein by reference as described under the heading “Where You Can Find Additional Information,” before buying any of the securities being offered. THIS PROSPECTUS MAY NOT BE USED TO CONSUMMATE A SALE OF SECURITIES UNLESS IT IS ACCOMPANIED BY A PROSPECTUS SUPPLEMENT.

You should rely only on the information that we have provided or incorporated by reference in this prospectus, any applicable prospectus supplement and any related free writing prospectus that we may authorize to be provided to you. We have not authorized anyone to provide you with different information. No dealer, salesperson or other person is authorized to give any information or to represent anything not contained in this prospectus, any applicable prospectus supplement or any related free writing prospectus that we may authorize to be provided to you. You must not rely on any unauthorized information or representation. This prospectus is an offer to sell only the securities offered hereby, but only under circumstances and in jurisdictions where it is lawful to do so. You should assume that the information in this prospectus, any applicable prospectus supplement or any related free writing prospectus is accurate only as of the date on the front of the document and that any information we have incorporated by reference is accurate only as of the date of the document incorporated by reference, regardless of the time of delivery of this prospectus, any applicable prospectus supplement or any related free writing prospectus, or any sale of a security.

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the heading “Where You Can Find Additional Information.”

CONVENTIONS THAT APPLY TO THIS PROSPECTUS

This prospectus contains estimates and other information concerning our target markets that are based on industry publications, surveys and forecasts, including those generated by SRI Consulting, a division of Access Intelligence, LLC, Chemical Market Associates, Inc., the US Energy Information Association (the “EIA”), the International Energy Agency (the “IEA”), the Renewable Fuels Association (the “RFA”) and Nexant, Inc. (“Nexant”). Certain target market sizes presented in this report have been calculated by us (as further described below) based on such information. This information involves a number of assumptions and limitations and you are cautioned not to give undue weight to this information. Please read the section of this prospectus entitled “Cautionary Statement Regarding Forward-Looking Statements.” The industry in which we operate is subject to a high degree of uncertainty and risk due to a variety of factors, including those described under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and in our most recent annual report on Form 10-K and any subsequently filed quarterly reports on Form 10-Q, as well as any amendments thereto reflected in subsequent filings with the SEC. These and other factors could cause actual results to differ materially from those expressed in these publications, surveys and forecasts.

With respect to calculation of product market volumes:

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product market volume calculations for fuels markets are based on data available for the year 2010 (the most current data available from the IEA);

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product market volume calculations for chemicals markets are based on data available for the year 2012 (the most current data available from Nexant); and

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volume data with respect to target market sizes is derived from data included in various industry publications, surveys and forecasts generated by the EIA, the IEA and Nexant.

We have converted these market sizes into volumes of isobutanol as follows:

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we calculated the size of the market for isobutanol as a gasoline blendstock and oxygenate by multiplying the world gasoline market volume by an estimated 12.5% by volume isobutanol blend ratio;

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we calculated the size of the specialty chemicals markets by substituting volumes of isobutanol equivalent to the volume of products currently used to serve these markets;

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for consistency in measurement, where necessary we converted all market sizes into gallons.

Conversion into gallons for the fuels markets is based upon fuel densities identified by Air BP Ltd. and the American Petroleum Institute.

GEVO, INC.

Gevo, Inc. is a renewable chemicals and next generation biofuels company. Our overall strategy is to commercialize biobased alternatives to petroleum-based products using a combination of synthetic biology and chemical technology. In order to implement this strategy, we are taking a building block approach. Initially, we intend to produce and sell isobutanol from renewable feedstocks. Isobutanol is a four carbon alcohol that can be sold directly for use as a specialty chemical in the production of solvents, paints, and coatings or as a value-added fuel blendstock. Isobutanol can also be converted into butenes using straightforward dehydration chemistry deployed in the refining and petrochemicals industries today. The convertibility of isobutanol into butenes is important because butenes are primary hydrocarbon building blocks used in the production of lubricants, rubber, plastics, fibers, other polymers and hydrocarbon fuels. We believe that the products derived from isobutanol have potential applications in approximately 40% of the global petrochemicals market, representing a potential market for isobutanol of approximately 70 billion gallons per year (“BGPY”), and substantially all of the global hydrocarbon fuels market, representing a potential market for isobutanol of approximately 950 BGPY. When combined with a potential specialty chemical market for isobutanol of approximately 1.2 BGPY, we believe that the potential global market for isobutanol is greater than 1,000 BGPY.

We believe that products derived from our isobutanol will be drop-in products, which means that our customers will be able to replace petroleum-based intermediate products with isobutanol-based intermediate products without modification to their equipment or production processes. The final products produced from our isobutanol-based intermediate products will be chemically and visually identical to those produced from petroleum-based intermediate products, except that they will contain carbon from renewable sources. Customer interest in our isobutanol is primarily driven by our production route, which we believe will be cost-efficient, and our isobutanol’s potential to serve as a cost-effective, environmentally sensitive alternative to the petroleum-based intermediate products that they currently use. We believe that at every step of the value chain, renewable products that are chemically identical to the incumbent petrochemical products will have lower market adoption hurdles in contrast with other bio-industrial products because the infrastructure and applications for such products already exist. In addition, we believe that products made from biobased isobutanol will be subject to less raw material cost volatility than the petroleum-based products in use today based on the historical cost volatility of agricultural feedstocks compared to oil.

In order to produce and sell isobutanol made from renewable sources, we have developed the Gevo Integrated Fermentation Technology^® (“GIFT^®”), an integrated technology platform for the efficient production and separation of isobutanol. GIFT^® consists of two components, proprietary biocatalysts which convert sugars derived from multiple renewable feedstocks into isobutanol through fermentation, and a proprietary separation unit which is designed to continuously separate isobutanol from water during the fermentation process. We developed our technology platform to be compatible with the existing approximately 23 BGPY of global operating ethanol production capacity, as estimated by the RFA. GIFT^® is designed to allow relatively low capital expenditure retrofits of existing ethanol facilities, enabling a rapid route to isobutanol production from the fermentation of renewable feedstocks. We believe that our production route will be cost-efficient and will enable rapid deployment of our technology platform and allow our isobutanol and the products produced from it to be economically competitive with many of the petroleum-based products used in the chemicals and fuels markets today.

We expect that the combination of our efficient proprietary technology, our marketing focus on providing drop-in substitutes for incumbent petrochemical products and our relatively low capital investment retrofit approach will mitigate many of the historical issues associated with the commercialization of renewable chemicals and fuels.

telephone number is (303) 858-8358. We maintain an Internet website at www.gevo.com. Information contained in or accessible through our website does not constitute part of this prospectus.

Unless otherwise mentioned or unless the context requires otherwise, all references in this prospectus to “we,” “us,” “our” and “Gevo^®” refer to Gevo, Inc., a Delaware corporation, and its wholly owned or indirect subsidiaries, and their predecessors.

RISK FACTORS

Investing in our securities involves a high degree of risk. You should carefully review the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents, including our most recent annual report on Form 10-K, and any subsequent quarterly reports on Form 10-Q and current reports on Form 8-K incorporated herein by reference or filed by us after the date of this prospectus, that are incorporated by reference into this prospectus. The occurrence of any of these risks might cause you to lose all or part of your investment in the offered securities. Additional risks not presently known to us or that we currently believe are immaterial may also significantly impair our business operations and financial condition.

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the documents incorporated by reference herein contain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”) and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). These statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, levels of activity, performance or achievements to be materially different from any future results, levels of activity, performances or achievements expressed or implied by the forward-looking statements. Forward-looking statements may include, but are not limited to, statements relating to the achievement of advances in our technology platform, the success of our retrofit production model, the availability of suitable and cost-competitive feedstocks, our ability to gain market acceptance for our products, the expected cost-competitiveness and relative performance attributes of our isobutanol and the products derived from it, additional competition, the future price and volatility of petroleum and products derived from petroleum and statements regarding our intended uses of the proceeds of the securities offered hereby. In some cases, you can identify forward-looking statements by terminology such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “believe,” “estimate,” “predict,” “potential” or “continue,” the negative of such terms or other comparable terminology.

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our inability to successfully commercialize isobutanol and the products derived from it;

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our inability to produce commercial quantities of isobutanol in a timely and economic manner;

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unexpected delays, operational difficulties, cost-overruns or failures in the retrofit process;

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our failure to successfully identify and acquire access to additional facilities suitable for efficient retrofitting;

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our failure to market our isobutanol to potential customers;

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fluctuations in the market price of petroleum;

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fluctuations in the market price of corn and other feedstocks;

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our inability to obtain regulatory approval for the use of our isobutanol in our target markets;

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our failure to adequately protect our intellectual property, or the loss of some of our intellectual property rights through costly litigation or administrative proceedings;

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our failure to transition our preliminary commitments into definitive supply and distribution agreements or to negotiate sufficient long-term supply agreements for our production of isobutanol; and

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general economic conditions and inflation, interest rate movements and access to capital.

forward-looking statements are set forth in under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and in our most recent annual report on Form 10-K and any subsequently filed quarterly reports on Form 10-Q, as well as any amendments thereto reflected in subsequent filings with the SEC. You should carefully read both this prospectus, the applicable prospectus supplement and any related free writing prospectus, together with the information incorporated herein by reference as described under the heading “Where You Can Find Additional Information,” completely and with the understanding that our actual future results may be materially different from what we expect.

THE SECURITIES WE MAY OFFER

We may offer shares of our common stock and preferred stock, various series of debt securities and/or warrants to purchase any of such securities, either individually or in units, with a total value of up to $250,000,000 from time to time under this prospectus at prices and on terms to be determined by market conditions at the time of any offering. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including, to the extent applicable:

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designation or classification;

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aggregate principal amount or aggregate offering price;

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maturity, if applicable;

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original issue discount, if any;

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rates and times of payment of interest or dividends, if any;

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redemption, conversion, exercise, exchange or sinking fund terms, if any;

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ranking;

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restrictive covenants, if any;

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voting or other rights, if any;

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conversion prices, if any; and

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important U.S. federal income tax considerations.

The prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add or update information contained in this prospectus or in documents we have incorporated by reference. However, no prospectus supplement or free writing prospectus will offer a security that is not registered and described in this prospectus at the time of the effectiveness of the registration statement of which this prospectus is a part.

THIS PROSPECTUS MAY NOT BE USED TO CONSUMMATE A SALE OF SECURITIES UNLESS IT IS ACCOMPANIED BY A PROSPECTUS SUPPLEMENT.

We may sell the securities directly to investors or to or through agents, underwriters or dealers. We, and our agents or underwriters, reserve the right to accept or reject all or part of any proposed purchase of securities. If we do offer securities to or through agents or underwriters, we will include in the applicable prospectus supplement:

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the names of those agents or underwriters;

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applicable fees, discounts and commissions to be paid to them;

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details regarding over-allotment options, if any; and

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the net proceeds to us.

Common Stock. We may issue shares of our common stock from time to time. The holders of common stock are entitled to one vote for each share held of record on all matters submitted to a vote of stockholders and do not have cumulative voting rights. Subject to preferences that may be applicable to any outstanding shares of preferred stock, the holders of common stock are entitled to receive ratably only those dividends as may be declared by our board of directors out of legally available funds. Upon our liquidation, dissolution or winding up, holders of our common stock are entitled to share ratably in all assets remaining after payment of liabilities and the liquidation preferences of any outstanding shares of preferred stock.

Preferred Stock. We may issue shares of our preferred stock from time to time, in one or more series. Under our amended and restated certificate of incorporation, our board of directors has the authority, without further action by stockholders, to designate up to 5,000,000 shares of preferred stock in one or more series and to fix the rights, preferences, privileges, qualifications and restrictions granted to or imposed upon the preferred stock, including dividend rights, conversion rights, voting rights, rights and terms of redemption, liquidation preferences and sinking fund terms, any or all of which may be greater than the rights of our common stock.

If we sell any series of preferred stock under this prospectus, we will fix the designations, powers, preferences and rights of such series of preferred stock, as well as the qualifications, limitations or restrictions thereon, in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock we are offering before the issuance of the related series of preferred stock. We urge you to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of preferred stock being offered, as well as the complete certificate of designation that contains the terms of the applicable series of preferred stock.

Debt Securities. We may issue debt securities from time to time, in one or more series, as either senior secured, senior unsecured or subordinated debt or as senior secured, senior unsecured or subordinated convertible debt. The subordinated debt securities will be subordinate and junior in right of payment, to the extent and in the manner described in the instrument governing the debt, to all of our senior indebtedness. Convertible debt securities will be convertible into or exchangeable for our common stock or our other securities. Conversion may be mandatory or at your option and would be at prescribed conversion rates.

The debt securities will be issued under one or more indentures, which are contracts between us and a national banking association or other eligible party, as trustee. In this prospectus, we have summarized certain general features of the debt securities. We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of debt securities being offered, as well as the complete indentures that contain the terms of the debt securities. Forms of indentures have been filed as exhibits to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

Warrants. We may issue warrants for the purchase of common stock, preferred stock and/or debt securities in one or more series. We may issue warrants independently or together with common stock, preferred stock and/or debt securities, and the warrants may be attached to or separate from these securities. In this prospectus, we have summarized certain general features of the warrants. We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the particular series of warrants being offered, as well as the complete warrant agreements and warrant certificates that contain the terms of the warrants. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants being offered.

We will evidence each series of warrants by warrant certificates that we will issue. Warrants may be issued under an applicable warrant agreement that we enter into with a warrant agent. We will indicate the name and address of the warrant agent, if applicable, in the prospectus supplement relating to the particular series of warrants being offered.

Units. We may issue, in one or more series, units consisting of common stock, preferred stock, debt securities and/or warrants for the purchase of common stock, preferred stock and/or debt securities in any combination. In this prospectus, we have summarized certain general features of the units. We urge you,

however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of units being offered, as well as the complete unit agreement that contains the terms of the units. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of unit agreement and any supplemental agreements that describe the terms of the series of units we are offering before the issuance of the related series of units.

We will evidence each series of units by unit certificates that we will issue. Units may be issued under a unit agreement that we enter into with a unit agent. We will indicate the name and address of the unit agent, if applicable, in the prospectus supplement relating to the particular series of units being offered.

RATIO OF EARNINGS TO FIXED CHARGES

The following summary is qualified by the more detailed information appearing in the computation table found in Exhibit 12.1 to the registration statement of which this prospectus is part and the historical financial statements, including the notes to those financial statements, incorporated by reference in this prospectus.

Our earnings are inadequate to cover fixed charges. The following table sets forth the dollar amount of the coverage deficiency for all periods (in thousands):


	Three Months Ended March 31, 2013			Year Ended December 31,
	Three Months Ended March 31, 2013			2012			2011			2010			2009			2008
Ratio of Earnings to Fixed Charges		—			—			—			—			—			—
Deficiency of Earnings Available to Cover Fixed Charges	$	(12,906	)	$	(62,044	)	$	(48,511	)	$	(40,112	)	$	(19,885	)	$	(14,542	)

USE OF PROCEEDS

Except as described in any prospectus supplement or in any related free writing prospectus that we may authorize to be provided to you, we currently intend to use the net proceeds from the sale of the securities offered hereby to acquire access to additional ethanol facilities through direct acquisition, tolling arrangements or joint ventures and to retrofit those facilities, as well as our existing facilities, to produce isobutanol. A portion of the net proceeds from this offering may also be used for general corporate purposes, including, among other things, working capital requirements and potential repayment of indebtedness that may be outstanding at the time of any offering under this prospectus. Pending these uses, we expect to invest the net proceeds in demand deposit accounts or short-term, investment-grade securities.

DESCRIPTION OF CAPITAL STOCK

Authorized and Outstanding Capital Stock

Our authorized capital stock consists of 100,000,000 shares of common stock, par value $0.01 per share, and 5,000,000 shares of preferred stock, par value $0.01 per share, issuable in one or more series designated by our board of directors. As of April 30, 2013, there were 44,080,138 shares of common stock and no shares of preferred stock outstanding.

Common Stock

The holders of our common stock have one vote per share. Holders of common stock are not entitled to vote cumulatively for the election of directors. Generally, all matters to be voted on by stockholders must be approved by a majority, or, in the case of election of directors, by a plurality, of the votes cast at a meeting at which a quorum is present, voting together as a single class, subject to any voting rights granted to holders of any then outstanding preferred stock. Subject to preferences that may be applicable to any then outstanding preferred stock, holders of our common stock are entitled to participate equally in dividends when and as dividends may be declared by our board of directors out of funds legally available for the payment of dividends. In the event of our voluntary or involuntary liquidation, dissolution or winding up, the prior rights of our creditors and the liquidation preference of any preferred stock then outstanding must first be satisfied. The holders of common stock will be entitled to share in the remaining assets on a pro rata basis. No shares of common stock are subject to redemption or have redemptive rights to purchase additional shares of common stock.

Our common stock is listed on the NASDAQ Global Market under the symbol “GEVO”.

Preferred Stock

Our amended and restated certificate of incorporation provides that we may issue shares of preferred stock from time to time in one or more series. Our board of directors is authorized to fix the voting rights, if any, designations, powers, preferences, qualifications, limitations and restrictions thereof, applicable to the shares of each series of preferred stock. The board of directors may, without stockholder approval, issue preferred stock with voting and other rights that could adversely affect the voting power and other rights of the holders of our common stock, including the likelihood that such holders will receive dividend payments and payments upon liquidation, and could have anti-takeover effects, including preferred stock or rights to acquire preferred stock in connection with implementing a stockholder rights plan. The ability of the board of directors to issue preferred stock without stockholder approval could have the effect of delaying, deferring or preventing a change of control or the removal of our existing management. There are currently no shares of preferred stock outstanding.

Anti-Takeover Provisions

The provisions of the Delaware General Corporation Law (the “DGCL”), our amended and restated certificate of incorporation, and our amended and restated bylaws contain provisions that could discourage or make more difficult a change in control of Gevo^®, including an acquisition of Gevo^® by means of a tender offer, a proxy contest and removal of our incumbent officers and directors, without the support of our board of directors. A summary of these provisions follows.

Statutory Business Combination Provision

We are subject to Section 203 of the DGCL (“Section 203”), which, subject to certain exceptions, prohibits a Delaware corporation from engaging in any “business combination” with an “interested stockholder” for a period of three years following the time that such stockholder became an interested stockholder, unless:

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the board of directors of the corporation approves either the business combination or the transaction that resulted in the stockholder becoming an interested stockholder, prior to the time the interested stockholder attained that status;

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upon the closing of the transaction that resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced, excluding, for purposes of determining the number of shares outstanding, those shares owned by persons who are directors and also officers and by employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or

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at or subsequent to such time, the business combination is approved by the board of directors and authorized at an annual or special meeting of stockholders, and not by written consent, by the affirmative vote of at least 66-2/3% of the outstanding voting stock that is not owned by the interested stockholder.

With certain exceptions, an “interested stockholder” is a person or group who or which owns 15% or more of the corporation’s outstanding voting stock (including any rights to acquire stock pursuant to an option, warrant, agreement, arrangement or understanding, or upon the exercise of conversion or exchange rights, and stock with respect to which the person has voting rights only), or is an affiliate or associate of the corporation and was the owner of 15% or more of such voting stock at any time within the previous three years.

In general, Section 203 defines a business combination to include:

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any merger or consolidation involving the corporation and the interested stockholder;

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any sale, transfer, pledge or other disposition of 10% or more of the assets of the corporation involving the interested stockholder;

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subject to certain exceptions, any transaction that results in the issuance or transfer by the corporation of any stock of the corporation to the interested stockholder;

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any transaction involving the corporation that has the effect of increasing the proportionate share of the stock of any class or series of the corporation beneficially owned by the interested stockholder; or

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the receipt by the interested stockholder of the benefit of any loans, advances, guarantees, pledges or other financial benefits provided by or through the corporation.

A Delaware corporation may “opt out” of this provision with an express provision in its original certificate of incorporation or an express provision in its amended and restated certificate of incorporation or bylaws resulting from a stockholders’ amendment approved by at least a majority of the outstanding voting shares. However, Gevo^® has not “opted out” of this provision. Section 203 could prohibit or delay mergers or other takeover or change-in-control attempts and, accordingly, may discourage attempts to acquire Gevo^®.

Election and Removal of Directors

Our amended and restated certificate of incorporation provides for our board of directors to be divided into three classes, with staggered three-year terms. Only one class of directors is elected at each annual meeting of our stockholders, with the other classes continuing for the remainder of their respective three-year terms. Because our stockholders do not have cumulative voting rights, our stockholders holding a majority of the shares of common stock outstanding are able to elect all of our directors. Directors may be removed only with cause by the affirmative vote of the holders of at least a majority of the outstanding shares entitled to vote on such removal.

No Stockholder Action by Written Consent

Our amended and restated certificate of incorporation and our amended and restated bylaws provide that any action required or permitted to be taken by the holders of common stock at an annual or special meeting of stockholders must be effected at a duly called meeting and may not be taken or effected by written consent of the stockholders.

Stockholder Meetings

Under our amended and restated certificate of incorporation and our amended and restated bylaws, only the board of directors, acting pursuant to a resolution adopted by a majority of the directors then in office, may call a special meeting of the stockholders, and any business conducted at any special meeting will be limited to the purpose or purposes specified in the notice for such special meeting.

Requirements for Advance Notification of Stockholder Nominations and Proposals

In order for our stockholders to bring nominations or business before an annual meeting properly, they must comply with certain notice requirements as provided by our amended and restated bylaws. Typically, in order for such notices to be timely, they must be provided to us not earlier than the close of business on the 120th day prior to the one-year anniversary of the preceding year’s annual meeting and not later than the close of business on the 90th day prior to the one-year anniversary of the preceding year’s annual meeting. For such notices to be timely in the event the annual meeting is advanced more than 30 days prior to or delayed by more than 70 days after the one-year anniversary of the preceding year’s annual meeting, notice must be provided to us not earlier than the close of business on the 120th day prior to such annual meeting and not later than the close of business on the later of the 90th day prior to such annual meeting or, if later, the 10th day following the day on which public announcement of the date of such meeting is first made.

Amendment of Charter Provisions

The affirmative vote of the holders of at least 66-2/3% of the voting power of all of the then-outstanding shares of our voting stock, voting together as a single class, is required to, among other things, alter, amend or repeal certain provisions of our amended and restated certificate of incorporation, including those related to the classification of our board of directors, the amendment of our bylaws and certificate of incorporation, restrictions against stockholder actions by written consent, the designated parties entitled to call a special meeting of the stockholders and the indemnification of officers and directors.

Our amended and restated bylaws may only be amended (or new bylaws adopted) by the board of directors or the affirmative vote of the holders of at least 66-2/3% of the voting power of all of the then-outstanding shares of our voting stock.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is American Stock Transfer & Trust Company. Its address is 6201 15th Avenue, Brooklyn, New York 11219 and its telephone number is (800) 937-5449. The transfer agent for any series of preferred stock that we may offer under this prospectus will be named and described in the prospectus supplement for that series.

DESCRIPTION OF DEBT SECURITIES

We may issue debt securities, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. While the terms we have summarized below will apply generally to any debt securities that we may offer under this prospectus, we will describe the particular terms of any debt securities that we may offer in more detail in the applicable prospectus supplement. The terms of any debt securities offered under a prospectus supplement may differ from the terms described below. Unless the context requires otherwise, whenever we refer to the indentures, we also are referring to any supplemental indentures that specify the terms of a particular series of debt securities.

We will issue the senior debt securities under the senior indenture that we will enter into with the trustee named in the senior indenture. We will issue the subordinated debt securities under the subordinated indenture that we will enter into with the trustee named in the subordinated indenture. The indentures will be qualified under the Trust Indenture Act of 1939. We use the term “debenture trustee” to refer to either the trustee under the senior indenture or the trustee under the subordinated indenture, as applicable. We have filed forms of indentures as exhibits to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

The following summaries of material provisions of the senior debt securities, the subordinated debt securities and the indentures are subject to, and qualified in their entirety by reference to, all of the provisions of the indenture applicable to a particular series of debt securities. We urge you to read the applicable prospectus supplements and any related free writing prospectuses related to the debt securities that we may offer under this prospectus, as well as the complete indentures that contain the terms of the debt securities. Except as we may otherwise indicate, the terms of the senior indenture and the subordinated indenture are identical.

General

We will describe in the applicable prospectus supplement the terms of the series of debt securities being offered, including:

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the title;

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the principal amount being offered, and if a series, the total amount authorized and the total amount outstanding;

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any limit on the amount that may be issued;

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whether or not we will issue the series of debt securities in global form, the terms and who the depositary will be;

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the maturity date;

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whether and under what circumstances, if any, we will pay additional amounts on any debt securities held by a person who is not a U.S. person for tax purposes, and whether we can redeem the debt securities if we have to pay such additional amounts;

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the annual interest rate, which may be fixed or variable, or the method for determining the rate and the date interest will begin to accrue, the dates interest will be payable and the regular record dates for interest payment dates or the method for determining such dates;

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whether or not the debt securities will be secured or unsecured, and the terms of any secured debt;

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the terms of the subordination of any series of subordinated debt;

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the place where payments will be payable;

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restrictions on transfer, sale or other assignment, if any;

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our right, if any, to defer payment of interest and the maximum length of any such deferral period;

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the date, if any, after which, and the price at which, we may, at our option, redeem the series of debt securities pursuant to any optional or provisional redemption provisions and the terms of those redemption provisions;

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the date, if any, on which, and the price at which we are obligated, pursuant to any mandatory sinking fund or analogous fund provisions or otherwise, to redeem, or at the holder’s option to purchase, the series of debt securities and the currency or currency unit in which the debt securities are payable;

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whether the indenture will restrict our ability and/or the ability of our subsidiaries to:

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incur additional indebtedness;

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issue additional securities;

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create liens;

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pay dividends and make distributions in respect of our capital stock and/or the capital stock of our subsidiaries;

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redeem capital stock;

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make investments or other restricted payments;

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sell, transfer or otherwise dispose of assets;

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enter into sale-leaseback transactions;

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engage in transactions with stockholders and affiliates;

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issue or sell stock of our subsidiaries; or

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effect a consolidation or merger;

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whether the indenture will require us to maintain any interest coverage, fixed charge, cash flow-based, asset-based or other financial ratios;

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information describing any book-entry features;

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provisions for a sinking fund purchase or other analogous fund, if any;

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the applicability of the provisions in the indenture on discharge;

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whether the debt securities are to be offered at a price such that they will be deemed to be offered at an “original issue discount” as defined in paragraph (a) of Section 1273 of the Internal Revenue Code;

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the denominations in which we will issue the series of debt securities, if other than denominations of $1,000 and any integral multiple thereof;

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the currency of payment of debt securities if other than U.S. dollars and the manner of determining the equivalent amount in U.S. dollars;

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any other specific terms, preferences, rights or limitations of, or restrictions on, the debt securities, including any additional events of default or covenants provided with respect to the debt securities, and any terms that may be required by us or advisable under applicable laws or regulations; and

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any other terms which shall not be inconsistent with the indentures.

The notes may be issued as original issue discount securities. An original issue discount security is a note, including any zero-coupon note, which:

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is issued at a price lower than the amount payable upon its stated maturity; and

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provides that upon redemption or acceleration of the maturity, an amount less than the amount payable upon the stated maturity, shall become due and payable.

United States federal income tax consequences applicable to notes sold at an original issue discount will be described in the applicable prospectus supplement. In addition, United States federal income tax or other consequences applicable to any notes which are denominated in a currency or currency unit other than United States dollars may be described in the applicable prospectus supplement.

Under the indentures, we will have the ability, in addition to the ability to issue notes with terms different from those of notes previously issued, without the consent of the holders, to reopen a previous issue of a series of notes and issue additional notes of that series, unless the reopening was restricted when the series was created, in an aggregate principal amount determined by us.

Conversion or Exchange Rights

We will set forth in the prospectus supplement the terms on which a series of debt securities may be convertible into or exchangeable for our common stock or our other securities. We will include provisions as to whether conversion or exchange is mandatory, at the option of the holder or at our option. We may include provisions pursuant to which the number of shares of our common stock or our other securities that the holders of the series of debt securities receive would be subject to adjustment.

Consolidation, Merger or Sale

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the indentures will not contain any covenant that restricts our ability to merge or consolidate, or sell, convey, transfer or otherwise dispose of all or substantially all of our assets. However, any successor to or acquiror of such assets must assume all of our obligations under the indentures or the debt securities, as appropriate. If the debt securities are convertible into or exchangeable for our other securities or securities of other entities, the person with whom we consolidate or merge or to whom we sell all of our property must make provisions for the conversion of the debt securities into securities that the holders of the debt securities would have received if they had converted the debt securities before the consolidation, merger or sale.

Events of Default Under the Indentures

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the following are events of default under the indentures with respect to any series of debt securities that we may issue:

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if we fail to pay interest when due and payable and our failure continues for 90 days and the time for payment has not been extended or deferred;

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if we fail to pay the principal, premium or sinking fund payment, if any, when due and payable and the time for payment has not been extended or delayed;

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if we fail to observe or perform any other covenant contained in the debt securities or the indentures, other than a covenant specifically relating to another series of debt securities, and our failure continues for 90 days after we receive notice from the debenture trustee or holders of at least 25% in aggregate principal amount of the outstanding debt securities of the applicable series;

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if specified events of bankruptcy, insolvency or reorganization occur; and

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any other event of default described in the applicable prospectus supplement.

If an event of default with respect to debt securities of any series occurs and is continuing, other than an event of default specified in the last bullet point above, the debenture trustee or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series, by notice to us in writing, and to the debenture trustee if notice is given by such holders, may declare the unpaid principal of, premium, if any, and

accrued interest, if any, due and payable immediately. If an event of default specified in the last bullet point above occurs with respect to us, the principal amount of and accrued interest, if any, of each issue of debt securities then outstanding shall be due and payable without any notice or other action on the part of the debenture trustee or any holder.

The holders of a majority in principal amount of the outstanding debt securities of an affected series may waive any default or event of default with respect to the series and its consequences, except defaults or events of default regarding payment of principal, premium, if any, or interest, unless we have cured the default or event of default in accordance with the indenture. Any such waiver shall cure the default or event of default.

Subject to the terms of the applicable indenture, if an event of default under an indenture shall occur and be continuing, the debenture trustee will be under no obligation to exercise any of its rights or powers under such indenture at the request or direction of any of the holders of the applicable series of debt securities, unless such holders have offered the debenture trustee reasonable indemnity. The holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the debenture trustee, or exercising any trust or power conferred on the debenture trustee, with respect to the debt securities of that series, provided that:

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the direction so given by the holders is not in conflict with any law or the applicable indenture; and

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subject to its duties under the Trust Indenture Act of 1939, the debenture trustee need not take any action that might involve it in personal liability or might be unduly prejudicial to the holders not involved in the proceeding.

A holder of the debt securities of any series will have the right to institute a proceeding under an indenture or to appoint a receiver or trustee, or to seek other remedies only if:

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the holder has given written notice to the debenture trustee of a continuing event of default with respect to that series;

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the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series have made written request, and such holders have offered reasonable indemnity to the debenture trustee to institute the proceeding as trustee; and

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the debenture trustee does not institute the proceeding, and does not receive from the holders of a majority in aggregate principal amount of the outstanding debt securities of that series other conflicting directions within 60 days after the notice, request and offer.

These limitations do not apply to a suit instituted by a holder of debt securities if we default in the payment of the principal, premium, if any, or accrued interest on, the debt securities.

We will periodically file statements with the debenture trustee regarding our compliance with specified covenants in the indentures.

Modification of Indenture; Waiver

We and the debenture trustee may change an indenture without the consent of any holders with respect to specific matters:

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to fix any ambiguity, defect or inconsistency in the indenture;

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to comply with the provisions described above under the heading “Description of Debt Securities—Consolidation, Merger or Sale;”

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to comply with any requirements of the SEC in connection with the qualification of any indenture under the Trust Indenture Act of 1939;

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to add to, delete from or revise the conditions, limitations, and restrictions on the authorized amount, terms, or purposes of issue, authentication and delivery of debt securities, as set forth in such indenture;

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to provide for the issuance of and establish the form and terms and conditions of the debt securities of any series as provided under the heading “Description of Debt Securities—General,” to establish the form of any certifications required to be furnished pursuant to the terms of an indenture or any series of debt securities, or to add to the rights of the holders of any series of debt securities;

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to evidence and provide for the acceptance of appointment hereunder by a successor trustee;

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to provide for uncertificated debt securities in addition to or in place of certificated debt securities and to make all appropriate changes for such purpose;

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to add to our covenants such new covenants, restrictions, conditions or provisions for the protection of the holders, and to make the occurrence, or the occurrence and the continuance, of a default in any such additional covenants, restrictions, conditions or provisions an event of default; or

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to change anything that does not materially adversely affect the interests of any holder of debt securities of any series.

In addition, under the indentures, the rights of holders of a series of debt securities may be changed by us and the debenture trustee with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding debt securities of each series that is affected. However, unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, we and the debenture trustee may make the following changes only with the consent of each holder of any outstanding debt securities affected:

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extending the fixed maturity of the series of debt securities;

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reducing the principal amount, reducing the rate of or extending the time of payment of interest, or reducing any premium payable upon the redemption of any debt securities;

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reducing the percentage of debt securities, the holders of which are required to consent to any amendment, supplement, modification or waiver of the applicable indenture or notes or for waiver of compliance with certain provisions of the applicable indenture or for waiver of certain defaults;.

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changing any of our obligations to pay additional amounts;

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reducing the amount of principal of an original issue discount security or any other note payable upon acceleration of the maturity thereof;

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changing currency in which any note or any premium or interest is payable;

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impairing the right to enforce any payment on or with respect to any note;

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adversely changing the right to convert or exchange, including decreasing the conversion rate or increasing the conversion price of, such note, if applicable;

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in the case of the subordinated indenture, modifying the subordination provisions in a manner adverse to the holders of the subordinated notes;

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if the notes are secured, changing the terms and conditions pursuant to which the notes are secured in a manner adverse to the holders of the secured notes;

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reducing the requirements contained in the applicable indenture for quorum or voting;

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changing any of our obligations to maintain an office or agency in the places and for the purposes required by the indentures; or

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modifying any of the above provisions set forth in this paragraph.

Discharge

Each indenture provides that we can elect to be discharged from our obligations with respect to one or more series of debt securities, except for specified obligations, including obligations to:

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replace stolen, lost or mutilated debt securities of the series;

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maintain paying agencies;

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hold monies for payment in trust;

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recover excess money held by the debenture trustee;

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compensate and indemnify the debenture trustee; and

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appoint any successor trustee.

In order to exercise our rights to be discharged, we must deposit with the debenture trustee money or government obligations sufficient to pay all the principal of, the premium, if any, and interest on, the debt securities of the series on the dates payments are due.

Form, Exchange and Transfer

We will issue the debt securities of each series only in fully registered form without coupons and, unless we provide otherwise in the applicable prospectus supplement, in denominations of $1,000 and any integral multiple thereof. The indentures provide that we may issue debt securities of a series in temporary or permanent global form and as book-entry securities that will be deposited with, or on behalf of, The Depository Trust Company (“DTC”) or another depositary named by us and identified in a prospectus supplement with respect to that series. See the section entitled “Legal Ownership of Securities” for a further description of the terms relating to any book-entry securities.

At the option of the holder, subject to the terms of the indentures and the limitations applicable to global securities described in the applicable prospectus supplement, the holder of the debt securities of any series can exchange the debt securities for other debt securities of the same series, in any authorized denomination and of like tenor and aggregate principal amount.

Subject to the terms of the indentures and the limitations applicable to global securities set forth in the applicable prospectus supplement, holders of the debt securities may present the debt securities for exchange or for registration of transfer, duly endorsed or with the form of transfer endorsed thereon duly executed if so required by us or the security registrar, at the office of the security registrar or at the office of any transfer agent designated by us for this purpose. Unless otherwise provided in the debt securities that the holder presents for transfer or exchange, we will impose no service charge for any registration of transfer or exchange, but we may require payment of any taxes or other governmental charges.

We will name in the applicable prospectus supplement the security registrar, and any transfer agent in addition to the security registrar, that we initially designate for any debt securities. We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each place of payment for the debt securities of each series.

If we elect to redeem the debt securities of any series, we will not be required to:

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issue, register the transfer of, or exchange any debt securities of that series during a period beginning at the opening of business 15 days before the day of mailing of a notice of redemption of any debt securities that may be selected for redemption and ending at the close of business on the day of the mailing; or

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register the transfer of or exchange any debt securities so selected for redemption, in whole or in part, except the unredeemed portion of any debt securities we are redeeming in part.

Information Concerning the Debenture Trustee

The debenture trustee, other than during the occurrence and continuance of an event of default under an indenture, undertakes to perform only those duties as are specifically set forth in the applicable indenture. Upon an event of default under an indenture, the debenture trustee must use the same degree of care as a prudent person would exercise or use in the conduct of his or her own affairs. Subject to this provision, the debenture trustee is under no obligation to exercise any of the powers given to it by the indentures at the request of any holder of debt securities unless it is offered reasonable security and indemnity against the costs, expenses and liabilities that it might incur.

Payment and Paying Agents

Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of the interest on any debt securities on any interest payment date to the person in whose name the debt securities, or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.

We will pay principal of, and any premium and interest on, the debt securities of a particular series at the office of the paying agents designated by us, except that unless we otherwise indicate in the applicable prospectus supplement, we will make interest payments by check that we will mail to the holder or by wire transfer to certain holders. Unless we otherwise indicate in the applicable prospectus supplement, we will designate the corporate trust office of the debenture trustee in the City of New York as our sole paying agent for payments with respect to debt securities of each series. We will name in the applicable prospectus supplement any other paying agents that we initially designate for the debt securities of a particular series. We will maintain a paying agent in each place of payment for the debt securities of a particular series.

All money we pay to a paying agent or the debenture trustee for the payment of the principal of, or any premium or interest on, any debt securities that remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the debt security thereafter may look only to us for payment thereof.

Governing Law

The indentures and the debt securities will be governed by and construed in accordance with the laws of the State of New York, except to the extent that the Trust Indenture Act of 1939 is applicable.

Subordination of Subordinated Debt Securities

The subordinated debt securities will be unsecured and will be subordinate and junior in priority of payment to certain of our other indebtedness to the extent described in a prospectus supplement. The subordinated indenture does not limit the amount of subordinated debt securities that we may issue, nor does it limit us from issuing any other secured or unsecured debt.

DESCRIPTION OF WARRANTS

We may issue warrants for the purchase of common stock, preferred stock and/or debt securities in one or more series. We may issue warrants independently or together with common stock, preferred stock and/or debt securities, and the warrants may be attached to or separate from these securities. While the terms summarized below will apply generally to any warrants that we may offer, we will describe the particular terms of any series of warrants in more detail in the applicable prospectus supplement. The terms of any warrants offered under a prospectus supplement may differ from the terms described below.

We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant agreement, including a form of warrant certificate, that describes the terms of the particular series of warrants we are offering before the issuance of the related series of warrants. The following summaries of material provisions of the warrants and the warrant agreements are subject to, and qualified in their entirety by reference to, all the provisions of the warrant agreement and warrant certificate applicable to the particular series of warrants that we may offer under this prospectus. We urge you to read the applicable prospectus supplements related to the particular series of warrants that we may offer under this prospectus, as well as any related free writing prospectuses, and the complete warrant agreements and warrant certificates that contain the terms of the warrants.

General

We will describe in the applicable prospectus supplement the terms of the series of warrants being offered, including:

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the offering price and aggregate number of warrants offered;

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the currency for which the warrants may be purchased;

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if applicable, the designation and terms of the securities with which the warrants are issued and the number of warrants issued with each such security or each principal amount of such security;

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if applicable, the date on and after which the warrants and the related securities will be separately transferable;

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in the case of warrants to purchase debt securities, the principal amount of debt securities purchasable upon exercise of one warrant and the price at which, and currency in which, this principal amount of debt securities may be purchased upon such exercise;

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in the case of warrants to purchase common stock or preferred stock, the number of shares of common stock or preferred stock, as the case may be, purchasable upon the exercise of one warrant and the price at which these shares may be purchased upon such exercise;

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the effect of any merger, consolidation, sale or other disposition of our business on the warrant agreements and the warrants;

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the terms of any rights to redeem or call the warrants;

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any provisions for changes to or adjustments in the exercise price or number of securities issuable upon exercise of the warrants;

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the dates on which the right to exercise the warrants will commence and expire;

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the manner in which the warrant agreements and warrants may be modified;

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a discussion of any material or special U.S. federal income tax consequences of holding or exercising the warrants;

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the terms of the securities issuable upon exercise of the warrants; and

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any other specific terms, preferences, rights or limitations of or restrictions on the warrants.

Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including:

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in the case of warrants to purchase debt securities, the right to receive payments of principal of, or premium, if any, or interest on the debt securities purchasable upon exercise or to enforce covenants in the applicable indenture; or

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in the case of warrants to purchase common stock or preferred stock, the right to receive dividends, if any, or payments upon our liquidation, dissolution or winding up or to exercise voting rights, if any.

Exercise of Warrants

Each warrant will entitle the holder to purchase the securities that we specify in the applicable prospectus supplement at the exercise price that we describe in the applicable prospectus supplement. Holders of the warrants may exercise the warrants at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement. After the specified time on the expiration date, unexercised warrants will become void.

Holders of the warrants may exercise the warrants by delivering the warrant certificate representing the warrants to be exercised together with specified information, and paying the required amount to the warrant agent in immediately available funds, as provided in the applicable prospectus supplement. We will set forth on the reverse side of the warrant certificate and in the applicable prospectus supplement the information that the holder of the warrant will be required to deliver to the warrant agent upon exercise.

Upon receipt of the required payment and the warrant certificate properly completed and duly executed at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement, we will issue and deliver the securities purchasable upon such exercise. If fewer than all of the warrants represented by the warrant certificate are exercised, then we will issue a new warrant certificate for the remaining amount of warrants. If we so indicate in the applicable prospectus supplement, holders of the warrants may surrender securities as all or part of the exercise price for warrants.

Governing Law

Unless we provide otherwise in the applicable prospectus supplement, the warrants and warrant agreements will be governed by and construed in accordance with the laws of the State of New York.

Enforceability of Rights by Holders of Warrants

Each warrant agent will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or trust with any holder of any warrant. A single bank or trust company may act as warrant agent for more than one issue of warrants. A warrant agent will have no duty or responsibility in case of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable upon exercise of, its warrants.

DESCRIPTION OF UNITS

We may issue, in one more series, units consisting of common stock, preferred stock, debt securities and/or warrants for the purchase of common stock, preferred stock and/or debt securities in any combination. While the terms we have summarized below will apply generally to any units that we may offer under this prospectus, we will describe the particular terms of any series of units in more detail in the applicable prospectus supplement. The terms of any units offered under a prospectus supplement may differ from the terms described below.

We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of unit agreement that describes the terms of the series of units we are offering, and any supplemental agreements, before the issuance of the related series of units. The following summaries of material terms and provisions of the units are subject to, and qualified in their entirety by reference to, all the provisions of the unit agreement and any supplemental agreements applicable to a particular series of units. We urge you to read the applicable prospectus supplements related to the particular series of units that we may offer under this prospectus, as well as any related free writing prospectuses and the complete unit agreement and any supplemental agreements that contain the terms of the units.

General

Each unit will be issued so that the holder of the unit is also the holder of each security included in the unit. Thus, the holder of a unit will have the rights and obligations of a holder of each included security. The unit agreement under which a unit is issued may provide that the securities included in the unit may not be held or transferred separately, at any time or at any time before a specified date.

We will describe in the applicable prospectus supplement the terms of the series of units being offered, including:

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the designation and terms of the units and of the securities comprising the units, including whether and under what circumstances those securities may be held or transferred separately;

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any provisions of the governing unit agreement that differ from those described below; and

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any provisions for the issuance, payment, settlement, transfer or exchange of the units or of the securities comprising the units.

The provisions described in this section, as well as those described under the headings “Description of Capital Stock,” “Description of Debt Securities” and “Description of Warrants” will apply to each unit and to any common stock, preferred stock, debt security or warrant included in each unit, respectively.

Issuance in Series

We may issue units in such amounts and in such numerous distinct series as we determine.

Enforceability of Rights by Holders of Units

Each unit agent will act solely as our agent under the applicable unit agreement and will not assume any obligation or relationship of agency or trust with any holder of any unit. A single bank or trust company may act as unit agent for more than one series of units. A unit agent will have no duty or responsibility in case of any default by us under the applicable unit agreement or unit, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a unit may, without the consent of the related unit agent or the holder of any other unit, enforce by appropriate legal action its rights as a holder under any security included in the unit.

Title

We, and any unit agent and any of their agents, may treat the registered holder of any unit certificate as an absolute owner of the units evidenced by that certificate for any purpose and as the person entitled to exercise the rights attaching to the units so requested, despite any notice to the contrary. See the section entitled “Legal Ownership of Securities” below.

LEGAL OWNERSHIP OF SECURITIES

We can issue securities in registered form or in the form of one or more global securities. We describe global securities in greater detail below. We refer to those persons who have securities registered in their own names on the books that we or any applicable trustee, depositary or warrant agent maintain for this purpose as the “holders” of those securities. These persons are the legal holders of the securities. We refer to those persons who, indirectly through others, own beneficial interests in securities that are not registered in their own names, as “indirect holders” of those securities. As we discuss below, indirect holders are not legal holders, and investors in securities issued in book-entry form or in street name will be indirect holders.

Book-Entry Holders

We may issue securities in book-entry form only, as we will specify in the applicable prospectus supplement. This means securities may be represented by one or more global securities registered in the name of a financial institution that holds them as depositary on behalf of other financial institutions that participate in the depositary’s book-entry system. These participating institutions, which are referred to as participants, in turn, hold beneficial interests in the securities on behalf of themselves or their customers.

Only the person in whose name a security is registered is recognized as the holder of that security. Securities issued in global form will be registered in the name of the depositary or its participants. Consequently, for securities issued in global form, we will recognize only the depositary as the holder of the securities, and we will make all payments on the securities to the depositary. The depositary passes along the payments it receives to its participants, which in turn pass the payments along to their customers who are the beneficial owners. The depositary and its participants do so under agreements they have made with one another or with their customers; they are not obligated to do so under the terms of the securities.

As a result, investors in a book-entry security will not own securities directly. Instead, they will own beneficial interests in a global security, through a bank, broker or other financial institution that participates in the depositary’s book-entry system or holds an interest through a participant. As long as the securities are issued in global form, investors will be indirect holders, and not holders, of the securities.

Street Name Holders

We may terminate a global security or issue securities in non-global form. In these cases, investors may choose to hold their securities in their own names or in “street name.” Securities held by an investor in street name would be registered in the name of a bank, broker or other financial institution that the investor chooses, and the investor would hold only a beneficial interest in those securities through an account he or she maintains at that institution.

For securities held in street name, we will recognize only the intermediary banks, brokers and other financial institutions in whose names the securities are registered as the holders of those securities, and we will make all payments on those securities to them. These institutions pass along the payments they receive to their customers who are the beneficial owners, but only because they agree to do so in their customer agreements or because they are legally required to do so. Investors who hold securities in street name will be indirect holders, not holders, of those securities.

Legal Holders

Our obligations, as well as the obligations of any applicable trustee and of any third parties employed by us or a trustee, run only to the legal holders of the securities. We do not have obligations to investors who hold beneficial interests in global securities, in street name or by any other indirect means. This will be the case whether an investor chooses to be an indirect holder of a security or has no choice because we are issuing the securities only in global form.

For example, once we make a payment or give a notice to the holder, we have no further responsibility for the payment or notice even if that holder is required, under agreements with depositary participants or customers or by law, to pass it along to the indirect holders but does not do so. Similarly, we may want to obtain the approval of the holders to amend an indenture, to relieve us of the consequences of a default or of our obligation to comply with a particular provision of the indenture or for other purposes. In such an event, we would seek approval only from the holders, and not the indirect holders, of the securities. Whether and how the holders contact the indirect holders is up to the holders.

Special Considerations For Indirect Holders

If you hold securities through a bank, broker or other financial institution, either in book-entry form or in street name, you should check with your own institution to find out:

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how it handles securities payments and notices;

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whether it imposes fees or charges;

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how it would handle a request for the holders’ consent, if ever required;

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whether and how you can instruct it to send you securities registered in your own name so you can be a holder, if that is permitted in the future;

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how it would exercise rights under the securities if there were a default or other event triggering the need for holders to act to protect their interests; and

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if the securities are in book-entry form, how the depositary’s rules and procedures will affect these matters.

Global Securities

A global security is a security that represents one or any other number of individual securities held by a depositary. Generally, all securities represented by the same global securities will have the same terms.

Each security issued in book-entry form will be represented by a global security that we deposit with and register in the name of a financial institution or its nominee that we select. The financial institution that we select for this purpose is called the depositary. Unless we specify otherwise in the applicable prospectus supplement, DTC will be the depositary for all securities issued in book-entry form.

A global security may not be transferred to or registered in the name of anyone other than the depositary, its nominee or a successor depositary, unless special termination situations arise. We describe those situations below under “Special Situations When a Global Security Will Be Terminated.” As a result of these arrangements, the depositary, or its nominee, will be the sole registered owner and holder of all securities represented by a global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of an account with a broker, bank or other financial institution that in turn has an account with the depositary or with another institution that does. Thus, an investor whose security is represented by a global security will not be a holder of the security, but only an indirect holder of a beneficial interest in the global security.

If the prospectus supplement for a particular security indicates that the security will be issued in global form only, then the security will be represented by a global security at all times unless and until the global security is terminated. If termination occurs, we may issue the securities through another book-entry clearing system or decide that the securities may no longer be held through any book-entry clearing system.

Special Considerations For Global Securities

The rights of an indirect holder relating to a global security will be governed by the account rules of the investor’s financial institution and of the depositary, as well as general laws relating to securities transfers. We do not recognize an indirect holder as a holder of securities and instead deal only with the depositary that holds the global security.

If securities are issued only in the form of a global security, an investor should be aware of the following:

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an investor cannot cause the securities to be registered in his or her name, and cannot obtain non-global certificates for his or her interest in the securities, except in the special situations we describe below;

•

an investor will be an indirect holder and must look to his or her own bank or broker for payments on the securities and protection of his or her legal rights relating to the securities, as we describe above;

•

an investor may not be able to sell interests in the securities to some insurance companies and to other institutions that are required by law to own their securities in non-book-entry form;

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an investor may not be able to pledge his or her interest in a global security in circumstances where certificates representing the securities must be delivered to the lender or other beneficiary of the pledge in order for the pledge to be effective;

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the depositary’s policies, which may change from time to time, will govern payments, transfers, exchanges and other matters relating to an investor’s interest in a global security;

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we and any applicable trustee have no responsibility for any aspect of the depositary’s actions or for its records of ownership interests in a global security, nor do we or any applicable trustee supervise the depositary in any way;

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the depositary may, and we understand that DTC will, require that those who purchase and sell interests in a global security within its book-entry system use immediately available funds, and your broker or bank may require you to do so as well; and

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financial institutions that participate in the depositary’s book-entry system, and through which an investor holds its interest in a global security, may also have their own policies affecting payments, notices and other matters relating to the securities.

There may be more than one financial intermediary in the chain of ownership for an investor. We do not monitor and are not responsible for the actions of any of those intermediaries.

Special Situations When a Global Security Will Be Terminated

In a few special situations described below, the global security will terminate and interests in it will be exchanged for physical certificates representing those interests. After that exchange, the choice of whether to hold securities directly or in street name will be up to the investor. Investors must consult their own banks or brokers to find out how to have their interests in securities transferred to their own name, so that they will be direct holders. We have described the rights of holders and street name investors above.

Unless we provide otherwise in the applicable prospectus supplement, the global security will terminate when the following special situations occur:

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if the depositary notifies us that it is unwilling, unable or no longer qualified to continue as depositary for that global security and we do not appoint another institution to act as depositary within 90 days;

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if we notify any applicable trustee that we wish to terminate that global security; or

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if an event of default has occurred with regard to securities represented by that global security and has not been cured or waived.

The prospectus supplement may also list additional situations for terminating a global security that would apply only to the particular series of securities covered by the applicable prospectus supplement. When a global security terminates, the depositary, and not we or any applicable trustee, is responsible for deciding the names of the institutions that will be the initial direct holders.

PLAN OF DISTRIBUTION

We may sell the securities from time to time pursuant to underwritten public offerings, negotiated transactions, block trades or a combination of these methods. We may sell the securities to or through underwriters or dealers, through agents, or directly to one or more purchasers. We may distribute securities from time to time in one or more transactions:

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at a fixed price or prices, which may be changed;

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at market prices prevailing at the time of sale;

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at prices related to such prevailing market prices; or

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at negotiated prices.

A prospectus supplement or supplements will describe the terms of the offering of the securities, including:

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the name or names of the underwriters, if any;

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the purchase price of the securities and the proceeds we will receive from the sale;

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any over-allotment options under which underwriters may purchase additional securities from us;

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any agency fees or underwriting discounts and other items constituting agents’ or underwriters’ compensation;

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any public offering price;

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any discounts or concessions allowed or reallowed or paid to dealers; and

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any securities exchange or market on which the securities may be listed.

Only underwriters named in the prospectus supplement will be underwriters of the securities offered by the prospectus supplement.

If underwriters are used in the sale, they will acquire the securities for their own account and may resell the securities from time to time in one or more transactions at a fixed public offering price or at varying prices determined at the time of sale. The obligations of the underwriters to purchase the securities will be subject to the conditions set forth in the applicable underwriting agreement. We may offer the securities to the public through underwriting syndicates represented by managing underwriters or by underwriters without a syndicate. Subject to certain conditions, the underwriters will be obligated to purchase all of the securities offered by the prospectus supplement, other than securities covered by any over-allotment option. Any public offering price and any discounts or concessions allowed or reallowed or paid to dealers may change from time to time. We may use underwriters with whom we have a material relationship. We will describe in the prospectus supplement, naming the underwriter, the nature of any such relationship.

We may sell securities directly or through agents we designate from time to time. We will name any agent involved in the offering and sale of securities and we will describe any commissions we will pay the agent in the prospectus supplement. Unless the prospectus supplement states otherwise, our agent will act on a best-efforts basis for the period of its appointment.

We may authorize agents or underwriters to solicit offers by certain types of institutional investors to purchase securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. We will describe the conditions to these contracts and the commissions we must pay for solicitation of these contracts in the prospectus supplement.

We may provide agents and underwriters with indemnification against civil liabilities, including liabilities under the Securities Act, or contribution with respect to payments that the agents or underwriters may make with respect to these liabilities. Agents and underwriters may engage in transactions with, or perform services for, us in the ordinary course of business.

All securities we may offer, other than common stock, will be new issues of securities with no established trading market. Any underwriters may make a market in these securities, but will not be obligated to do so and may discontinue any market making at any time without notice. We cannot guarantee the liquidity of the trading markets for any securities.

Any underwriter may engage in over-allotment, stabilizing transactions, short-covering transactions and penalty bids in accordance with Regulation M under the Exchange Act. Over-allotment involves sales in excess of the offering size, which create a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum price. Syndicate-covering or other short-covering transactions involve purchases of the securities, either through exercise of the over-allotment option or in the open market after the distribution is completed, to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a stabilizing or covering transaction to cover short positions. Those activities may cause the price of the securities to be higher than it would otherwise be. If commenced, the underwriters may discontinue any of the activities at any time.

Any underwriters that are qualified market makers on the NASDAQ Global Market may engage in passive market making transactions in the common stock on the NASDAQ Global Market in accordance with Regulation M under the Exchange Act, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the common stock. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded. Passive market making may stabilize the market price of the securities at a level above that which might otherwise prevail in the open market and, if commenced, may be discontinued at any time.

In compliance with guidelines of the Financial Industry Regulatory Authority, or FINRA, the maximum consideration or discount to be received by any FINRA member or independent broker dealer may not exceed 8% of the aggregate amount of the securities offered pursuant to this prospectus and any applicable prospectus supplement.

LEGAL MATTERS

The validity of the securities being offered by this prospectus will be passed upon by Paul Hastings LLP, San Diego, California.

EXPERTS

The consolidated financial statements incorporated in this Prospectus by reference from the Company’s Annual Report on Form 10-K have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their report (which report expresses an unqualified opinion on the consolidated financial statements and includes an explanatory paragraph referring to Gevo Inc.’s status as a development stage enterprise), which is incorporated herein by reference. Such consolidated financial statements have been so incorporated in reliance upon the report of such firm given upon their authority as experts in accounting and auditing.

MATERIAL CHANGES

None.

WHERE YOU CAN FIND ADDITIONAL INFORMATION

Available Information

This prospectus is part of a registration statement that we have filed with the SEC relating to the securities to be offered. This prospectus does not contain all of the information we have included in the registration statement and the accompanying exhibits and schedules in accordance with the rules and regulations of the SEC, and we refer you to the omitted information. The statements this prospectus makes pertaining to the content of any contract, agreement or other document that is an exhibit to the registration statement necessarily are summaries of their material provisions and do not describe all exceptions and qualifications contained in those contracts, agreements or documents. You should read those contracts, agreements or documents for information that may be important to you. The registration statement, exhibits and schedules are available at the SEC’s Public Reference Room or through its Internet website.

Incorporation by Reference

The rules of the SEC allow us to incorporate by reference in this prospectus the information in other documents that we file with it, which means that we can disclose important information to you by referring you to those documents that we have filed separately with the SEC. You should read the information incorporated by reference because it is an important part of this prospectus. We hereby incorporate by reference the following information or documents into this prospectus:

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our Annual Report on Form 10-K for the fiscal year ended December 31, 2012 filed with the SEC on March 26, 2013;

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our Amendment No. 1 to the Annual Report on Form 10-K for the fiscal year ended December 31, 2012 filed with the SEC on April 12, 2013;

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our Quarterly Report on Form 10-Q for the quarter ended March 31, 2013 filed with the SEC on May 6, 2013;

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our Current Reports on Form 8-K filed with the SEC on January 2, 2013, March 5, 2013, March 20, 2013, March 21, 2013 and April 30, 2013; and

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Any information in any of the foregoing documents will automatically be deemed to be modified or superseded to the extent that information in this prospectus or in a later filed document that is incorporated or deemed to be incorporated herein by reference modifies or replaces such information.

Any statements in any such future filings will automatically be deemed to modify and supersede any information in any document we previously filed with the SEC that is incorporated or deemed to be incorporated herein by reference to the extent that statements in the later filed document modify or replace such earlier statements.

Upon written or oral request, we will provide to you, without charge, a copy of any or all of the documents that are incorporated by reference into this prospectus but not delivered with the prospectus, including exhibits which are specifically incorporated by reference into such documents. Requests should be directed to: Gevo, Inc., Attention: Investor Relations, 345 Inverness Drive South, Building C, Suite 310, Englewood, Colorado, 80112, telephone (303) 858-8358.

LOGO

Gevo, Inc.

Common Stock Units

Consisting of One Share of Common Stock and

A Warrant to Purchase of a Share of Common Stock

PROSPECTUS

December , 2013