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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1. Name and Address of Reporting Person * Cross Atlantic Capital Partners, Inc.   2. Issuer Name and Ticker or Trading Symbol Rubicon Technology, Inc. [RBCN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) FIVE RADNOR CORPORATE CENTER, SUITE 555, 100 MATSONFORD ROAD 3. Date of Earliest Transaction (Month/Day/Year) 06/21/2010 (Street) RADNOR, PA 19087 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) ___ Form filed by One Reporting Person _X_ 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 06/21/2010   S   500,000 (1) (2) D $ 28.41 5,386,423 (1) (3) I See Footnote (1)

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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
Cross Atlantic Capital Partners, Inc. FIVE RADNOR CORPORATE CENTER, SUITE 555 100 MATSONFORD ROAD RADNOR, PA 19087		X
CROSS ATLANTIC TECHNOLOGY FUND L P FIVE RADNOR CORPORATE CENTER, SUITE 555 100 MATSONFORD ROAD RADNOR, PA 19087		X
XATF Management, L.P. FIVE RADNOR CORPORATE CENTER, SUITE 555 100 MATSONFORD ROAD RADNOR, PA 19087		X
CROSS ATLANTIC TECHNOLOGY FUND II LP FIVE RADNOR CORPORATE CENTER, SUITE 555 100 MATSONFORD ROAD RADNOR, PA 19087		X
XATF MANAGEMENT II LP FIVE RADNOR CORPORATE CENTER, SUITE 555 100 MATSONFORD ROAD RADNOR, PA 19087		X
CROSS ATLANTIC CAPITAL PARTNERS II INC FIVE RADNOR CORPORATE CENTER, SUITE 555 100 MATSONFORD ROAD RADNOR, PA 19087		X
CO INVESTMENT 2000 FUND LP FIVE RADNOR CORPORATE CENTER, SUITE 555 100 MATSONFORD ROAD RADNOR, PA 19087		X
Co-Invest Management LP FIVE RADNOR CORPORATE CENTER, SUITE 555 100 MATSONFORD ROAD RADNOR, PA 19087		X
Co-Invest Capital Partners Inc FIVE RADNOR CORPORATE CENTER, SUITE 555 100 MATSONFORD ROAD RADNOR, PA 19087		X

Signatures

/s/ Scott Glickson, attorney-in-fact		06/22/2010
**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 shares held by Cross Atlantic Technology Fund, L.P., Cross Atlantic Technology Fund, II, L.P., and/or The Co-Investment 2000 Fund, L.P. Donald R. Caldwell, a director of the issuer, is the owner and director of Cross Atlantic Capital Partners, Inc., which is the general partner of XATF Management, L.P., which is the general partner of Cross Atlantic Technology Fund, L.P. Donald R. Caldwell 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. Donald R. Caldwell 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.
(2)	As part of the issuer's secondary offering, Cross Atlantic Technology Fund, L.P. sold 59,121 shares of its common stock, Cross Atlantic Technology Fund II, L.P. sold 208,534 shares of its common stock and The Co-Investment 2000 Fund, L.P. sold 232,345 shares of its common stock.
(3)	After the sale of shares in the issuer's secondary offering, Cross Atlantic Technology Fund, L.P. holds 668,572 shares of common stock, Cross Atlantic Technology Fund II, L.P. holds 2,230,198 shares of common stock and The Co-Investment 2000 Fund, L.P. holds 2,487,653 shares of common stock.

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