SCHEDULE 13G CUSIP NO. 232808105 PAGE 1 OF 14 PAGES UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G UNDER THE SECURITIES EXCHANGE ACT OF 1934 (AMENDMENT NO. 3)* Questcor Pharmaceuticals, Inc. (Name of Issuer) Common Stock, no par value (Title of Class of Securities) 232808105 (CUSIP Number) December 31, 2005 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [ ] Rule 13d-1(b) [X] 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 disclosures provided in a prior cover page. The information required on 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). SCHEDULE 13G CUSIP NO. 232808105 PAGE 2 OF 14 PAGES - -------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON I.R.S. IDENTIFICATION NO. OF ABOVE PERSON (ENTITIES ONLY) Delta Opportunity Fund, Ltd. - -------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (A) [ ] (B) [ ] (See Item 6) - -------------------------------------------------------------------------------- 3 SEC USE ONLY - -------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION British Virgin Islands - -------------------------------------------------------------------------------- 5 SOLE VOTING POWER -0- ----------------------------------------------------------------- NUMBER OF 6 SHARED VOTING POWER SHARES BENEFICIALLY 1,012,546 shares of Common Stock (See Item 4(a)) OWNED BY ----------------------------------------------------------------- EACH 7 SOLE DISPOSITIVE POWER REPORTING PERSON -0- WITH: ----------------------------------------------------------------- 8 SHARED DISPOSITIVE POWER 1,012,546 shares of Common Stock (See Item 4(a)) - -------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,012,546 shares of Common Stock (See Item 4(a)) - -------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) [ ] - -------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 1.9% (See Item 4(a)) - -------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) CO - -------------------------------------------------------------------------------- SCHEDULE 13G CUSIP NO. 232808105 PAGE 3 OF 14 PAGES - -------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON I.R.S. IDENTIFICATION NO. OF ABOVE PERSON (ENTITIES ONLY) Delta Opportunity Fund (Institutional), LLC 13-4040413 - -------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (A) [ ] (B) [ ] (See Item 6) - -------------------------------------------------------------------------------- 3 SEC USE ONLY - -------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION Delaware - -------------------------------------------------------------------------------- 5 SOLE VOTING POWER -0- ----------------------------------------------------------------- NUMBER OF 6 SHARED VOTING POWER SHARES BENEFICIALLY 733,223 shares of Common Stock (See Item 4(a)) OWNED BY ----------------------------------------------------------------- EACH 7 SOLE DISPOSITIVE POWER REPORTING PERSON -0- WITH: ----------------------------------------------------------------- 8 SHARED DISPOSITIVE POWER 733,223 shares of Common Stock (See Item 4(a)) - -------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 733,223 shares of Common Stock (See Item 4(a)) - -------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) [ ] - -------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 1.4% (See Item 4(a)) - -------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) OO - -------------------------------------------------------------------------------- SCHEDULE 13G CUSIP NO. 232808105 PAGE 4 OF 14 PAGES - -------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON I.R.S. IDENTIFICATION NO. OF ABOVE PERSON (ENTITIES ONLY) Arthur G. Altschul, Jr. - -------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (A) [ ] (B) [ ] (See Item 6) - -------------------------------------------------------------------------------- 3 SEC USE ONLY - -------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION United States of America - -------------------------------------------------------------------------------- 5 SOLE VOTING POWER -0- ----------------------------------------------------------------- NUMBER OF 6 SHARED VOTING POWER SHARES BENEFICIALLY 1,745,769 shares of Common Stock (See Item 4(a)) OWNED BY ----------------------------------------------------------------- EACH 7 SOLE DISPOSITIVE POWER REPORTING PERSON -0- WITH: ----------------------------------------------------------------- 8 SHARED DISPOSITIVE POWER 1,745,769 shares of Common Stock (See Item 4(a)) - -------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,745,769 shares of Common Stock (See Item 4(a)) - -------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) [ ] - -------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 3.2% (See Item 4(a)) - -------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) IN - -------------------------------------------------------------------------------- SCHEDULE 13G CUSIP NO. 232808105 PAGE 5 OF 14 PAGES - -------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON I.R.S. IDENTIFICATION NO. OF ABOVE PERSON (ENTITIES ONLY) Reinaldo M. Diaz - -------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (A) [ ] (B) [ ] (See Item 6) - -------------------------------------------------------------------------------- 3 SEC USE ONLY - -------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION United States of America - -------------------------------------------------------------------------------- 5 SOLE VOTING POWER -0- ----------------------------------------------------------------- NUMBER OF 6 SHARED VOTING POWER SHARES BENEFICIALLY 1,745,769 shares of Common Stock (See Item 4(a)) OWNED BY ----------------------------------------------------------------- EACH 7 SOLE DISPOSITIVE POWER REPORTING PERSON -0- WITH: ----------------------------------------------------------------- 8 SHARED DISPOSITIVE POWER 1,745,769 shares of Common Stock (See Item 4(a)) - -------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,745,769 shares of Common Stock (See Item 4(a)) - -------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) [ ] - -------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 3.2% (See Item 4(a)) - -------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) IN - -------------------------------------------------------------------------------- SCHEDULE 13G CUSIP NO. 232808105 PAGE 6 OF 14 PAGES - -------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON I.R.S. IDENTIFICATION NO. OF ABOVE PERSON (ENTITIES ONLY) Diaz & Altschul Advisors, LLC 13-3940170 - -------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (A)[ ] (B)[ ] (See Item 6) - -------------------------------------------------------------------------------- 3 SEC USE ONLY - -------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION New York - -------------------------------------------------------------------------------- 5 SOLE VOTING POWER -0- ----------------------------------------------------------------- NUMBER OF 6 SHARED VOTING POWER SHARES BENEFICIALLY 1,745,769 shares of Common Stock (See Item 4(a)) OWNED BY ----------------------------------------------------------------- EACH 7 SOLE DISPOSITIVE POWER REPORTING PERSON -0- WITH: ----------------------------------------------------------------- 8 SHARED DISPOSITIVE POWER 1,745,769 shares of Common Stock (See Item 4(a)) - -------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,745,769 shares of Common Stock (See Item 4(a)) - -------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) [ ] - -------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 3.2% (See Item 4(a)) - -------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) OO - -------------------------------------------------------------------------------- SCHEDULE 13G CUSIP NO. 232808105 PAGE 7 OF 14 PAGES - -------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON I.R.S. IDENTIFICATION NO. OF ABOVE PERSON (ENTITIES ONLY) Diaz & Altschul Management, LLC 06-1502204 - -------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (A)[ ] (B)[ ] - -------------------------------------------------------------------------------- 3 SEC USE ONLY - -------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION Delaware - -------------------------------------------------------------------------------- 5 SOLE VOTING POWER -0- ----------------------------------------------------------------- NUMBER OF 6 SHARED VOTING POWER SHARES BENEFICIALLY 733,223 shares of Common Stock (See Item 4(a)) OWNED BY ----------------------------------------------------------------- EACH 7 SOLE DISPOSITIVE POWER REPORTING PERSON -0- WITH: ----------------------------------------------------------------- 8 SHARED DISPOSITIVE POWER 733,223 shares of Common Stock (See Item 4(a)) - -------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 733,223 shares of Common Stock (See Item 4(a)) - -------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) [ ] - -------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 1.4% (See Item 4(a)) - -------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) OO - -------------------------------------------------------------------------------- SCHEDULE 13G CUSIP NO. 232808105 PAGE 8 OF 14 PAGES Item 1(a). Name of Issuer: Questcor Pharmaceuticals, Inc. (the "Issuer") Item 1(b). Address of Issuer's Principal Executive Offices: 3260 Whipple Road Union City, California 94587 Item 2(a). Names of Persons Filing: Delta Opportunity Fund, Ltd. ("Delta") Delta Opportunity Fund (Institutional), LLC ("Institutional") Arthur G. Altschul, Jr. ("Altschul") Reinaldo M. Diaz ("Diaz") Diaz & Altschul Advisors, LLC ("Advisors") Diaz & Altschul Management, LLC ("Management") Item 2(b). Address of Principal Business Office: Delta - c/o SEI Investments, Styne House, Upper Hatch Street Dublin 2, Ireland Institutional - 122 East 42nd Street, Suite 2500, New York, New York 10168 Altschul - 122 East 42nd Street, Suite 2500, New York, New York 10168 Diaz - 122 East 42nd Street, Suite 2500, New York, New York 10168 Advisors - 122 East 42nd Street, Suite 2500, New York, New York 10168 Management - 122 East 42nd Street, Suite 2500, New York, New York 10168 Item 2(c). Place of Organization or Citizenship: Delta - British Virgin Islands Institutional - Delaware Altschul - United States of America Diaz - United States of America Advisors - New York Management - Delaware Item 2(d). Title of Class of Securities: Common Stock, no par value per share, of the Issuer (the "Common Stock") Item 2(e). CUSIP Number: 232808105 Item 3. This Schedule is filed pursuant to Rule 13d-1(c) by Altschul, Diaz, Delta, Institutional, Advisors and Management. SCHEDULE 13G CUSIP NO. 232808105 PAGE 9 OF 14 PAGES Item 4. Ownership: (a) Amount Beneficially Owned: Altschul: 1,745,769 shares* Diaz: 1,745,769 shares* Delta: 1,012,546 shares* Institutional: 733,223 shares* Advisors: 1,745,769 shares* Management: 733,223 shares* (b) Percent of Class: Altschul: 3.2% Diaz: 3.2% Delta: 1.9% Institutional: 1.4% Advisors: 3.2% Management: 1.4% (Based on 52,880,502 shares of Common Stock outstanding, as of November 7, 2005, as reported in the Issuer's Quarterly Report on Form 10-Q for the quarter ended September 30, 2005.) (c) Number of Shares as to which the Person has: Altschul, Diaz and Advisors: (i) sole power to vote or to direct the vote -0- (ii) shared power to vote or to direct the vote: 1,745,769 shares of Common Stock* (iii) sole power to dispose or to direct the disposition of -0- (iv) shared power to dispose or to direct the disposition of 1,745,769 shares of Common Stock* Delta: (i) sole power to vote or to direct the vote -0- (ii) shared power to vote or to direct the vote: SCHEDULE 13G CUSIP NO. 232808105 PAGE 10 OF 14 PAGES 1,012,546 shares of Common Stock* (iii) sole power to dispose or to direct the disposition of -0- (iv) shared power to dispose or to direct the disposition of 1,012,546 shares of Common Stock* Institutional and Management: (i) sole power to vote or to direct the vote -0- (ii) shared power to vote or to direct the vote: 733,223 shares of Common Stock* (iii) sole power to dispose or to direct the disposition of -0- (iv) shared power to dispose or to direct the disposition of 733,223 shares of Common Stock* * All beneficial ownership amounts are shown as of January 4, 2006. Advisors serves as investment advisor to Delta and Institutional. By reason of such relationships, Advisors may be deemed to share voting and dispositive power over the shares of Common Stock owned by Delta and Institutional. Advisors disclaims beneficial ownership of such shares of Common Stock. Management serves as investment manager to and managing member of Institutional. By reason of such relationships, Management may be deemed to share voting and dispositive power over the shares of Common Stock listed as beneficially owned by Institutional. Management disclaims beneficial ownership of such shares of Common Stock. Altschul is a member of the parent company of Advisors and is a member of Management. By reason of such relationships, Altschul may be deemed to share voting and dispositive power over the shares of Common Stock listed as beneficially owned by Advisors and Management. Altschul disclaims beneficial ownership of such shares of Common Stock listed as beneficially owned by Advisors and Management. Diaz is a member of the parent company of Advisors and is a member of Management. By reason of such relationships, Diaz may be deemed to share voting and dispositive power over the shares of Common Stock listed as beneficially owned by Advisors and Management. Diaz disclaims beneficial SCHEDULE 13G CUSIP NO. 232808105 PAGE 11 OF 14 PAGES ownership of such shares of Common Stock listed as beneficially owned by Advisors and Management. The shares of Common Stock reported as beneficially owned are held by Delta and Institutional. Altschul, Diaz, Advisors and Management disclaim beneficial ownership of such shares of Common Stock. Delta and Institutional each disclaims beneficial ownership of shares of Common Stock reported on this Schedule as beneficially owned by any other person identified on this Schedule. Certain of the shares of Common Stock reported as beneficially owned by Altschul, Diaz, Delta, Institutional, Advisors and Management are shares of Common Stock which each such person has the right to acquire upon exercise of warrants (the "Warrants") to purchase shares of Common Stock as follows: Altschul, Diaz, and Advisors: 1,189,969 Delta: 690,182 shares Institutional and Management: 499,787 shares Item 5. Ownership of Five Percent or Less of a Class: If this statement is being filed to report the fact that as of the date hereof each of the Reporting Persons ceased to be the beneficial owner of more than five percent of the class of securities, check the following [X] 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 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. SCHEDULE 13G CUSIP NO. 232808105 PAGE 12 OF 14 PAGES Exhibits: Exhibit I: Joint Filing Agreement, dated as of January 28, 2003, by and among Altschul, Diaz, Delta, Institutional, Advisors and Management (incorporated herein by reference to the exhibit with the same number filed with Schedule 13G filed by the persons reporting on this Amendment No. 3). SCHEDULE 13G CUSIP NO. 232808105 PAGE 13 OF 14 PAGES SIGNATURE By signing below I certify that, to the best of my knowledge and belief, the securities referred to above 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. Dated as of February 13, 2006 DELTA OPPORTUNITY FUND, LTD. By: DIAZ & ALTSCHUL ADVISORS, LLC, as Investment Advisor By: /s/ Robert Lewis ------------------------------------ Robert Lewis Chief Financial Officer DELTA OPPORTUNITY FUND (INSTITUTIONAL), LLC By: DIAZ & ALTSCHUL MANAGEMENT, LLC, as Managing Member By: /s/ Robert Lewis ------------------------------------ Robert Lewis Chief Financial Officer /s/ Arthur G. Altschul, Jr. ---------------------------------------- Arthur G. Altschul, Jr. /s/ Reinaldo M. Diaz ---------------------------------------- Reinaldo M. Diaz DIAZ & ALTSCHUL ADVISORS, LLC By: DIAZ & ALTSCHUL CAPITAL MANAGEMENT, LLC, as Managing Member By: /s/ Robert Lewis ------------------------------------ Robert Lewis Chief Financial Officer SCHEDULE 13G CUSIP NO. 232808105 PAGE 14 OF 14 PAGES DIAZ & ALTSCHUL MANAGEMENT, LLC By: /s/ Robert Lewis ------------------------------------ Robert Lewis Chief Financial Officer