424B3
 

Filed Pursuant to Rule 424(b)(3)
Registration No. 333-123677
Prospectus Supplement No. 3 dated December 20, 2005
(To Prospectus dated June 2, 2005)
NRG LOGO
NRG Energy, Inc.
420,000 Shares of 4% Convertible Perpetual Preferred Stock
10,500,000 Shares of Common Stock issuable upon conversion of the Preferred Stock
      This Prospectus Supplement supplements the prospectus dated June 2, 2005 (the “Prospectus”) of NRG Energy, Inc., relating to the sale by certain of our stockholders (including their pledgees, donees, assignees, transferees, successors and others who later hold any of the selling stockholders’ interests) of up to 420,000 shares of preferred stock, or 10,500,000 shares of our common stock issuable upon conversion of the preferred stock. You should read this Prospectus Supplement in conjunction with the Prospectus, and this Prospectus Supplement is qualified by reference to the Prospectus, except to the extent that the information in this Prospectus Supplement supersedes the information contained in the Prospectus.
      Investing in our preferred stock or common stock involves risks that are described in the “Risk Factors” section beginning on page 6 of the Prospectus.
      Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this Prospectus Supplement is truthful or complete. Any representation to the contrary is a criminal offense.
The date of this Prospectus Supplement is December 20, 2005

 

The table of selling stockholders contained in the Prospectus is hereby superseded by the following table.
                                                         
                    Securities Offered by        
    Ownership Before Offering     the Prospectus (1)     Ownership After Offering (2)  
Name   Preferred     Common (3)     Preferred     Commons (3)     Preferred     Common     % of Common (4)  
1976 Distribution Trust FBO A.R. Lauder/Zinterhofer
     6       150       6       150       0       0       0  
2000 Revocable Trust FBO A.R. Lauder/Zinterhofer
     5       125       5       125       0       0       0  
Advent Claymore Enhance Growth & Income Fund
     2,435       60,875       2,435       60,875       0       0       0  
Advent Convertible Master (Cayman), L.P.
     6,723       168,075       6,723       168,075       0       0       0  
Alcon Laboratories
     641       16,025       641       16,025       0       0       0  
AM International EMAC 63 Ltd.
     790       19,750       790       19,750       0       0       0  
AM Master Fund I, LP
     6,916       172,900       6,916       172,900       0       0       0  
Anthony Munk
     607       15,175       607       15,175       0       0       0  
Arlington County Employees Retirement Systems
     1,032       25,800       1,032       25,800       0       0       0  
Asante Health Systems
     205       5,125       205       5,125       0       0       0  
BBT Fund, L.P.
     8,850       221,250       8,850       221,250       0       0       0  
Boston Income Portfolio c/o Eaton Vance Management High Yield Group
     1,255       31,375       1,255       31,375       0       0       0  
Citigroup Global Markets, Inc.(5)
   5,000       125,000       5,000       125,000       0       0       0  
City of New York Fire Dept Pension Fund High Yield
     125       3,125       125       3,125       0       0       0  
City of New York Police Pension Fund High Yield
     275       6,875       275       6,875       0       0       0  
City of New York Teachers Retirement System High Yield
     375       9,375       375       9,375       0       0       0  
City University of New York
     215       5,375       215       5,375       0       0       0  
CNHCA Master Account, LP
     5,500       137,500       5,500       137,500       0       0       0  
Coastal Convertibles Ltd.
     1,500       37,500       1,500       37,500       0       0       0  
Concentrated Alpha Partners LP
     6,750       168,750       6,750       168,750       0       0       0  

2

 

                                                         
                    Securities Offered by        
    Ownership Before Offering     the Prospectus (1)     Ownership After Offering (2)  
Name   Preferred     Common (3)     Preferred     Commons (3)     Preferred     Common     % of Common (4)  
DBAG London
     11,000       275,000       11,000       275,000       0       0       0
Delaware Dividend Income Fund
     1,500       37,500       1,500       37,500       0       0       0
Delaware Public Employees Retirement Systems
     1,857       46,425       1,857       46,425       0       0       0
Deutsche Bank Securities Inc.
     1,500       37,500       1,500       37,500       0       0       0
Diversified High Yield Bond Fund c/o Eaton Vance Management High Yield Group
     245       6,125       245       6,125       0       0       0
Drawbridge Convertible I Ltd.
     489       12,225       489       12,225       0       0       0
Drawbridge Convertible II Ltd.
     156       3,900       156       3,900       0       0       0
Drawbridge Global Macro Masterfund Ltd.
     3,310       82,750       3,310       82,750       0       0       0
ELCA Unscreened — High Yield
     275       6,875       275       6,875       0       0       0
Fidelity Financial Trust: Fidelity Strategic Dividend & Income Fund(6)
     3,900       97,500       3,900       97,500       0       0       0
Fore Convertible Master Fund, Ltd.
     25,220       630,500       25,220       630,500       0       0       0
Fore Erisa Fund, Ltd.
     2,790       69,750       2,790       69,750       0       0       0
Frontpoint Convertible Arbitrage Fund LP
     5,000       125,000       5,000       125,000       0       0       0
GLG Market Neutral Fund
     22,000       550,000       22,000       550,000       0       0       0
Grace Convertible Arbitrage Fund, Ltd.
     7,000       175,000       7,000       175,000       0       0       0
Grady Hospital
     201       5,025       201       5,025       0       0       0
Guggenheim Portfolio Company VIII (Cayman) Ltd.
     2,511       62,775       2,511       62,775       0       0       0
Guggenheim Portfolio Company XXXI, LLC
     5,000       125,000       5,000       125,000       0       0       0
Hallmark Master Trust High Yield Fund c/o Eaton Vance Management High Yield Group
     70       1,750       70       1,750       0       0       0

3

 

                                                         
                    Securities Offered by        
    Ownership Before Offering     the Prospectus (1)     Ownership After Offering (2)  
Name   Preferred     Common (3)     Preferred     Commons (3)     Preferred     Common     % of Common (4)  
HFR CA Opportunity Mgt. Trst.
     340       8,500       340       8,500       0       0       0  
HFR CA Select Fund
     750       18,750       750       18,750       0       0       0  
HFR RVA Combined Master Trust
     2,000       50,000       2,000       50,000       0       0       0  
High Income Portfolio c/o Eaton Vance Management High Yield Group
     865       21,625       865       21,625       0       0       0  
IAM National Pension Fund
     375       9,375       375       9,375       0       0       0  
Independence Blue Cross
     623       15,575       623       15,575       0       0       0  
Industriens Pensionsforsikring
     175       4,375       175       4,375       0       0       0  
ING Convertible Fund
     1,920       48,000       1,920       48,000       0       0       0  
ING CP Convertible Portfolio
     80       2,000       80       2,000       0       0       0  
ING MFS Utilities Portfolio
     40       1,000       40       1,000       0       78,520       *  
ING T. RowePrice Capital Appreciation Portfolio
     12,000       300,000       12,000       300,000       0       0       0  
Intl Union of Operating Engineers (ENG) c/o Eaton Vance Management High Yield Group
     15       375       15       375       0       0       0  
JHVST MidCap Value B
     200       5,000       200       5,000       0       47,200       *  
JMG Capital Partners, Inc
     2,350       58,750       2,350       58,750       0       0       0  
JMG Triton Offshore Ltd.
     2,850       71,250       2,850       71,250       0       0       0  
John Hancock Funds II — Spectrum Income Fund
     100       2,500       100       2,500       0       0       0  
John Hancock Trust — Spectrum Income Trust
     100       2,500       100       2,500       0       0       0  
John Hancock Trust Utilities Trust
     100       2,500       100       2,500       0       131,140       *  
John Hancock Variable Series Trust I — Mid Cap Value
     200       5,000       200       5,000       0       26,800       *  
4

 

                                                         
                    Securities Offered by        
    Ownership Before Offering     the Prospectus (1)     Ownership After Offering (2)  
Name   Preferred     Common (3)     Preferred     Commons (3)     Preferred     Common     % of Common (4)  
JP Morgan Securities, Inc.
     2,500       62,500       2,500       62,500       0       0       0  
Kamunting Street Master Fund, Ltd.
     22,500       562,500       22,500       562,500       0       0       0  
KBC Financial Products USA, Inc.
     8,955       223,875       8,955       223,875       0       0       0  
KDC Convertible Arbitrage Fund LP
     3,000       75,000       3,000       75,000       0       0       0  
Laborers District Council & Contractors Pension FD of Ohio
     200       5,000       200       5,000       0       14,400       *  
LIJ Invest — Global High Yield
     275       6,875       275       6,875       0       0       0  
Lyxor
     465       11,625       465       11,625       0       0       0  
Lyxor/AM Investment Fund Ltd.
     988       24,700       988       24,700       0       0       0  
Lyxor/Silverado Fund LTD
     1,550       38,750       1,550       38,750       0       0       0  
Man Mac I, Ltd.
     9,390       234,750       9,390       234,750       0       0       0  
McMahan Securities Co. LP
     45       1,125       45       1,125       0       0       0  
MFS Utilities Fund, a Series of MFS Series Trust VI
     1,355       33,875       1,355       33,875       0       1,581,000       1.96 %
MFS Variable Insurance Trust — MFS Utilities Series
     820       20,500       820       20,500       0       853,900       1.06 %
MFS/Sun Life Series Trust:
                                                        
Utilities Series
     324       8,100       324       8,100       0       355,700       *  
MSS Convertible Arbitrage 1
     20       500       20       500       0       0       0  
National Bank of Canada
     1,186       29,650       1,186       29,650       0       0       0  
New Orleans Firefighters Pension/Relief Fund
     126       3,150       126       3,150       0       0       0  
New York City Employees Retirement Systems Enhanced Fund
     475       11,875       475       11,875       0       0       0  
Newport Alternative Income Fund
     2,972       74,300       2,972       74,300       0       0       0  
5

 

                                                         
                    Securities Offered by        
    Ownership Before Offering     the Prospectus (1)     Ownership After Offering (2)  
Name   Preferred     Common (3)     Preferred     Commons (3)     Preferred     Common     % of Common (4)  
NMS Services (Cayman) Inc.
     1,176       29,400       1,176       29,400       0       0       0  
Northern Income Equity Fund
     2,460       61,500       2,460       61,500       0       0       0  
Occidental Petroleum Corporation
     114       2,850       114       2,850       0       0       0  
Pebble Limited Partnership
     2,083       52,075       2,083       52,075       0       0       0  
Penn Series Flexibly Managed Fund
     5,600       140,000       5,600       140,000       0       0       0  
Penn Series High Yield Bond Fund
     200       5,000       200       5,000       0       0       0  
PensionsInvest — Global High Yield
     250       6,250       250       6,250       0       0       0  
PFA Invest — Global High Yield
     450       11,250       450       11,250       0       0       0  
PIMCO Convertible Fund
     500       12,500       500       12,500       0       0       0  
Policeman and Fireman Retirement System of the City of Detroit
     500       12,500       500       12,500       0       0       0  
Pro-Mutual
     1,357       33,925       1,357       33,925       0       0       0  
RWDSU Local 338 High Yield Fund c/o Eaton Vance Management High Yield Fund
     20       500       20       500       0       0       0  
S.A.C. Arbitrage Fund, LLC
     8,000       200,000       8,000       200,000       0       0       0  
Sage Capital Management LLC
     3,000       75,000       3,000       75,000       0       0       0  
Salomon Brothers Asset Management, Inc.(7)
     6,600       165,000       6,600       165,000       0       0       0  
SEPTA High Yield Fund c/o Eaton Vance Management High Yield Fund
     20       500       20       500       0       0       0  
Severn River Master Fund c/o Morgan Stanley
     1,000       25,000       1,000       25,000       0       0       0  
Silver Point Capital Fund LP
     1,365       34,125       1,365       34,125       0       1,008,208       1.25  
Silver Point Capital Offhsore Fund, Ltd.
     2,135       53,375       2,135       53,375       0       1,601,365       1.98  

6

 

                                                         
                    Securities Offered by        
    Ownership Before Offering     the Prospectus (1)     Ownership After Offering (2)  
Name   Preferred     Common (3)     Preferred     Common (3)     Preferred     Common     % of Common (4)  
Silverado Arbitrage Trading, Ltd.
     500       12,500       500       12,500       0       10,000       *  
SOCS Ltd.
     10,000       250,000       8,000       200,000       2,000       50,000       *  
Sphinx Fund
     140       3,500       140       3,500       0     0       0  
SRI Fund, L.P.
     1,500       37,500       1,500       37,500       0       0       0  
Stanfield Offshore Leveraged Assets, Ltd.
     10,500       262,500       10,500       262,500       0       430,713       *  
T. RowePrice Capital Appreciation Fund
     33,600       840,000       33,600       840,000       0       0       0  
T. RowePrice High Yield Fund
     4,350       108,750       4,350       108,750       0       0       0  
T. RowePrice Mid-Cap Value Fund
     12,000       300,000       12,000       300,000       0       912,500       1.13 %
The New America High Income Fund
     375       9,375       375       9,375       0       0       0  
TQA Master Fund, LTD.
     870       21,750       870       21,750       0       0       0  
TQA Masters Plus Fund, LTD.
     1,510       37,750       1,510       37,750       0       0       0  
TRP Institutional High Yield Fund
     375       9,375       375       9,375       0       0       0  
TRP Invest — Global High Yield
     925       23,125       75       1,875       850       21,250       *  
TRP SICAV Global High Yield Bond Fund
     1,125       28,125       1,125       28,125       0       0       0  
Trustmark Insurance
     393       9,825       393       9,825       0       0       0  
UBS AG London F/B/O HFS
     5,000       125,000       5,000       125,000       0       0       0  
UBS AG London FBO PFEL
     18,500       462,500       18,500       462,500       0       0       0  
UBS AG London FBO WCBP
     7,000       175,000       7,000       175,000       0       0       0  

7

 

                                                         
                    Securities Offered by        
    Ownership Before Offering     the Prospectus (1)     Ownership After Offering (2)  
Name   Preferred     Common (3)     Preferred     Commons (3)     Preferred     Common     % of Common (4)  
UBS O’Connor LLC F/B/O O’Connor Global Convertiable Arbitrage Master Ltd.
     5,000       125,000       5,000       125,000       0       0       0  
Volkswagen High Yield Bond Fund c/o Eaton Vance Management High Yield Group
     10       250       10       250       0       0       0  
Whitebox Convertible Arbitrage Partners LP
     26,000       650,000       26,000       650,000       0       0       0  
Whitebox Diversified Convertible Arbitrage Partners LP
     5,000       125,000       5,000       125,000       0       0       0  
Xavex – Convertible Arbitrage 7 Fund
     150       3,750       150       3,750       0       0       0  
Zazove Convertible Arbitrage Fund, LP
     4,000       100,000       4,000       100,000       0       0       0  
Zazove Hedged Convertible Fund, LP
     2,000       50,000       2,000       50,000       0       0       0  
Zurich Institutional Benchmarks Master Fund LTD c/o TQA Investors, LLC
     180       4,500       180       4,500       0       0       0  
Zurich Institutional Benchmarks Master Fund Ltd. c/o Forest Investment Management Fund
     2,061       51,525       2,061       51,525       0       0       0  

8

 

 
* Less than 1%.
(1)  Amounts indicated may be in excess of the total amount registered due to sales or transfers exempt from the registration requirements of the Securities Act of 1933, as amended, since the date upon which the selling stockholders provided to us the information regarding their preferred stock.
 
(2)  The information regarding the beneficial ownership after resale of shares is based on the assumption that each selling stockholder will sell all of the shares of preferred stock and common stock owned by the selling stockholder and covered by the Prospectus.
 
(3)  Unless otherwise indicated, includes all shares of common stock issuable upon conversion of the preferred stock and assumes a conversion price of $40.00 per share, which is equal to an approximate conversion rate of 25 shares per share of preferred stock. However, this conversion price will be subject to adjustment as described under “Description of the Preferred Stock — Conversion Rights” in the Prospectus. As a result, the number of shares of common stock beneficially owned prior to this offering and the number of shares of common stock offered hereby may increase or decrease in the future.
 
(4)  Based on 80,701,888 shares of common stock outstanding as of December 16, 2005.
 
(5)  Citigroup Global Markets Inc. was a co-placement agent on the issuance of the preferred stock.
 
(6)  The entity is a registered investment fund advised by Fidelity Management & Research Company (“FMR Co.”), a registered investment adviser under the Investment Advisers Act of 1940, as amended. FMR Co., 82 Devonshire Street, Boston, Massachusetts 02190, a wholly-owned subsidiary of FMR Corp. and an investment adviser registered under Section 203 of the Investment Advisers Act of 1940, is the beneficial owner of 2,402,699 shares of our outstanding common stock as a result of acting as investment adviser to various investment companies registered under Section 8 of the Investment Company Act of 1940.
 
(7)  Salomon Brothers Asset Management, Inc. acts as discretionary investment advisor with respect to certain accounts that hold the preferred stock. Accordingly, Salomon Brothers Asset Management, Inc. may be deemed to be the beneficial owner of such preferred stock. Salomon Brothers Asset Management, Inc. is the beneficial owner and, therefore, the Selling Stockholder of the following accounts: General Motors Investment Corp. (5,000 shares), General Motors Broad Mandate (600 shares) and Smith Barney Convertible Fund (1,000 shares).

9