Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
CALDWELL DONALD R
   2. Issuer Name and Ticker or Trading Symbol
Rubicon Technology, Inc. [RBCN] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
C/O RUBICON TECHNOLOGY, INC., 900 EAST GREEN ST., UNIT A		 3. Date of Earliest Transaction (Month/Day/Year)
01/01/2016
(Street)

BENSENVILLE, IL 60106		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 01/01/2016   A   69,517 (1) A $ 0 105,050 (2) D (3)  
Common Stock               2,217,851 (4) (5) I See footnote. (4)

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
CALDWELL DONALD R
C/O RUBICON TECHNOLOGY, INC.
900 EAST GREEN ST., UNIT A
BENSENVILLE, IL 60106		   X      

Signatures

 /s/ Scott Glickson, attorney-in-fact for Donald R. Caldwell   01/05/2016
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Consists of restricted stock pursuant to grants that vest according to the following schedule: 17,379 shares vest on March 31, 2016, 17,379 shares vest on June 30, 2016, 17,379 shares vest on September 30, 2016 and 17,380 shares vest on December 31, 2016.
(2) Includes 69,517 shares of restricted stock pursuant to grants that vest as indicated in footnote 1.
(3) Under the terms of the applicable partnership agreements of the Funds (as defined below), the Reporting Person is deemed to hold the newly acquired shares plus an additional 28,433 shares (for a total of 97,950 shares), for the benefit of the Funds, which are entitled to receive the net economic benefit of the shares as a credit against the management fees owed by the Funds to Cross Atlantic Capital Partners, Inc. The Reporting Person disclaims beneficial ownership of the shares except to the extent of his pecuniary interest therein.
(4) Consists of shares held by Cross Atlantic Technology Fund, II, L.P. and/or The Co-Investment 2000 Fund, L.P. (the "Funds"). The Reporting Person is the owner and director of Cross Atlantic Capital Partners, Inc., which is the investment manager for each of the Funds. The Reporting Person is a director, shareholder and officer of Cross Atlantic Capital Partners II, Inc., which is the general partner of XATF Management II, L.P., which is the general partner of Cross Atlantic Technology Fund II, L.P. The Reporting Person is a shareholder, director and officer of Co-Invest Capital Partners, Inc., which is the general partner of Co-Invest Management, L.P., which is the general partner of The Co-Investment 2000 Fund, L.P. The Reporting Person disclaims beneficial ownership of the shares held by the Funds except to the extent of his pecuniary interest therein.
(5) Cross Atlantic Technology Fund II, L.P. holds 1,047,698 shares of common stock and The Co-Investment 2000 Fund, L.P. holds 1,170,153 shares of common stock.

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