SEC FORM 3

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person^*

CALDWELL DONALD R

(Last)

(First)

(Middle)

C/O RUBICON TECHNOLOGY INC.

9931 FRANKLIN AVENUE

(Street)

FRANKLIN PARK

60131

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
11/15/2007

3. Issuer Name and Ticker or Trading Symbol
Rubicon Technology, Inc. [ RBCN ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

5. If Amendment, Date of 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

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	265,078	I	See Footnotes⁽¹⁾⁽²⁾

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
Series A Preferred	⁽³⁾⁽⁴⁾	⁽³⁾⁽⁴⁾	Common Stock	957,560⁽³⁾⁽⁴⁾	⁽³⁾⁽⁴⁾	I	See Footnotes⁽¹⁾⁽⁵⁾
Series B-2 Convertible Preferred	⁽³⁾⁽⁴⁾	⁽³⁾⁽⁴⁾	Common Stock	1,575,124⁽³⁾⁽⁴⁾	⁽³⁾⁽⁴⁾	I	See Footnotes⁽¹⁾⁽⁶⁾
Series C-2 Convertible Preferred	⁽³⁾⁽⁴⁾	⁽³⁾⁽⁴⁾	Common Stock	1,433,056⁽³⁾⁽⁴⁾	⁽³⁾⁽⁴⁾	I	See Footnotes⁽¹⁾⁽⁷⁾
Series D-2 Convertible Preferred	⁽³⁾⁽⁴⁾	⁽³⁾⁽⁴⁾	Common Stock	510,945⁽³⁾⁽⁴⁾	⁽³⁾⁽⁴⁾	I	See Footnotes⁽¹⁾⁽⁸⁾
Series E Convertible Preferred	⁽³⁾⁽⁴⁾	⁽³⁾⁽⁴⁾	Common Stock	3,262,323⁽³⁾⁽⁴⁾	⁽³⁾⁽⁴⁾	I	See Footnotes⁽¹⁾⁽⁹⁾
Warrants to Purchase Series B-2 Preferred	⁽³⁾⁽⁴⁾	04/15/2008	Common Stock	18,197⁽³⁾⁽⁴⁾	⁽³⁾⁽⁴⁾	I	See Footnotes⁽¹⁾⁽¹⁰⁾
Warrants to Purchase Series B-2 Preferred	⁽³⁾⁽⁴⁾	06/10/2008	Common Stock	18,197⁽³⁾⁽⁴⁾	⁽³⁾⁽⁴⁾	I	See Footnotes⁽¹⁾⁽¹⁰⁾
Warrants to Purchase Series E Preferred	⁽³⁾⁽⁴⁾	12/15/2015	Common Stock	243,446⁽³⁾⁽⁴⁾	⁽³⁾⁽⁴⁾	I	See Footnotes⁽¹⁾⁽¹¹⁾
Warrants to Purchase Series E Preferred	⁽³⁾⁽⁴⁾	01/27/2016	Common Stock	24,380⁽³⁾⁽⁴⁾	⁽³⁾⁽⁴⁾	I	See Footnotes⁽¹⁾⁽¹²⁾

Explanation of Responses:

1. Consists of shares held by or issuable to Cross Atlantic Technology Fund, L.P., 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 general partner of XATF Management, L.P., which is the general partner of Cross Atlantic Technology Fund, L.P. 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.

2. Consists of 132,539 shares held by Cross Atlantic Technology Fund, L.P. and 132,539 shares held by The Co-Investment 2000 Fund, L.P.

3. The preferred shares are immediately convertible. The warrants are immediately exercisable. Each share of preferred stock will convert automatically into common stock upon the closing of the issuer's initial public offering according to the following ratios: Series A Preferred Stock on a one-to-0.5536 ratio; Series B-2 Convertible Preferred Stock on a one-to-0.1535 ratio; Series C-2 Convertible Preferred Stock on a one-to-0.1009 ratio; Series D-2 Convertible Preferred Stock on a one-to-0.1246 ratio and Series E Convertible Preferred Stock on a one-to-0.0769 ratio. Each warrant for preferred shares will convert automatically into warrants of common stock upon the closing of the issuer's initial public offering according to the same ratios. (Continued with Footnote No. 4)

4. Amounts shown include shares of common stock issuable upon such conversion in exchange for accrued dividends on the preferred stock at the following rates: Series A at $ 9.6083 per share, Series B-2 at $ 3.6478 per share, Series C-2 at $ 7.5595 per share, Series D-2 at $ 6.6690 per share and Series E at $ 3.6478 per share.

5. Consists of 478,780 shares issuable to Cross Atlantic Technology Fund, L.P. and 478,780 shares issuable to The Co-Investment 2000 Fund, L.P.

6. Consists of 322,985 shares issuable to Cross Atlantic Technology Fund, L.P. and 1,252,139 shares issuable to The Co-Investment 2000 Fund, L.P.

7. Consists of 716,528 shares issuable to Cross Atlantic Technology Fund II, L.P. and 716,528 shares issuable to The Co-Investment 2000 Fund, L.P.

8. Consists of 160,454 shares issuable to Cross Atlantic Technology Fund II, L.P. and 350,491 shares issuable to The Co-Investment 2000 Fund, L.P.

9. Consists of 2,439,690 shares issuable to Cross Atlantic Technology Fund II. L.P., 44,929 shares issuable to Cross Atlantic Technology Fund L.P., and 777,704 shares issuable to The Co-Investment 2000 Fund L.P.

10. Represents, effective upon the initial public offering, warrants to purchase 3,731 shares of common stock held by Cross Atlantic Technology Fund, L.P. and warrants to purchase 14,466 shares of common stock held by The Co-Investment Fund, L.P.

11. Represents, effective upon the initial public offering, warrants to purchase 114,177 shares of common stock held by Cross Atlantic Technology Fund II, L.P. and warrants to purchase 129,269 shares of common stock held by The Co-Investment 2000 Fund, L.P.

12. Represents, effective upon the initial public offering, warrants to purchase 13,826 shares of common stock held by Cross Atlantic Technology Fund II, L.P. and warrants to purchase 10,554 shares of common stock held by The Co-Investment 2000 Fund, L.P.

	/s/ Scott Glickson, attorney-in-fact	11/15/2007
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (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).
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