UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 Rubicon Technology, Inc. (Name of Issuer) Common Stock (Title of Class of Securities) 78112T107 (CUSIP Number) October 31, 2011 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [X] Rule 13d-1(b) [ ] Rule 13d-1(c) [ ] Rule 13d-1(d) *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). CUSIP No. 78112T107 1. Names of Reporting Person Sparta Asset Management, LLC I.R.S. Identification Nos. of above persons: 26-0703880 2. Check the Appropriate Box if a Member Of a Group [ ] (a) [ ] (b) 3. SEC Use Only 4. Citizenship or Place of Organization Delaware, United States 5. Sole Voting Power: 1,047,998 Number of Shares 6. Shared Voting Power: 0 Beneficially Owned by 7. Sole Dispositive Power: 2,337,377 Each Reporting Person With 8. Shared Dispositive Power: 0 9. Aggregate Amount Beneficially Owned by Each Reporting Person 2,337,377 10. Check if the Aggregate Amount in Row (9) Excludes Certain Shares 11. Percent of Class Represented by Amount in Row (9) 10.15% 12. Type of Reporting Person IA Item 1. (a) Name of Issuer: Rubicon Technology, Inc (b) Address of Issuer's Principal Executive Offices: 900 East Green Street Bensenville, Illinois 60106 Item 2. (a) Name of Person Filing: Sparta Asset Management, LLC (b) Address of Principal Business Office, or, if None, Residence: One O'Hare Centre 6250 N. River Road, Suite 1000 Rosemont, IL 60018 United States (c) Citizenship: Please see Item 4 on each cover sheet for each Reporting Person. (d) Title of Class of Securities Common Stock (e) CUSIP Number: 78112T107 Item 3. Sparta Asset Management, LLC is an investment adviser in accordance with ss.240.13d-1(b)(1)(ii)(E). Item 4. Ownership Please see Items 5-9 and 11 on each cover sheet for each Reporting Person. Item 5. Ownership of Five Percent or Less of a Class Not Applicable Item 6. Ownership of More than Five Percent on Behalf of Another Person Not Applicable Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company Not Applicable Item 8. Identification and Classification of Members of the Group Not Applicable Item 9. Notice of Dissolution of Group Not Applicable Item 10. Certification By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect. SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Date: November 14, 2011 Sparta Asset Management, LLC By: /s/ Ryan Carr -------------------------- Name: Ryan Carr Title: Chief Investment Officer Managing Partner