STRUCTURED PRODUCTS CORP CASTSM STEP UP TR FOR MORG STAN NTS
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Not applicable.
Not applicable.
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The Certificates representing investors' interest in the Trust are               represented by one or more physical Certificates registered in the               name of Cede & Co., the nominee of The Depository Trust Company.                The Certificates are listed on the New York Stock Exchange.
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Not Applicable
Not Applicable   Item 8.      Financial Statements and Supplementary Data                None
None
Not applicable
Not applicable                                      PART III
None
Not Applicable
Information required by Item 201(d) of Regulation S-X:               Not applicable               Information required by Item 403 of Regulation S-X: None
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Not Applicable                                     PART IV
(a)     The following documents are also filed as part of this Report:          3.  Exhibits:              31.1     Certification by Assistant Secretary, Assistant Vice                     President and Finance Officer of the Registrant pursuant to                     15 U.S.C. Section 7241, as adopted pursuant to Section 302                     of the Sarbanes-Oxley Act of 2002.             99.1     Annual Compliance Report by Trustee.             99.2     Report of Aston Bell & Associates.   (b)     The following reports on Form 8-K were filed during the period covered by this report and are hereby incorporated by reference:               1.    Trustee's Distribution Statement for the January 1, 2005                    Distribution Date filed on Form 8-K on January 12, 2005.               2.    Trustee's Distribution Statement for the February 1, 2005                    Distribution Date filed on Form 8-K on February 15, 2005.               3.    Trustee's Distribution Statement for the March 1, 2005                    Distribution Date filed on Form 8-K on March 15, 2005.               4.    Trustee's Distribution Statement for the April 1, 2005                    Distribution Date filed on Form 8-K on April 13, 2005.               5.    Trustee's Distribution Statement for the May 1, 2005                    Distribution Date filed on Form 8-K on May 16, 2005.               6.    Trustee's Distribution Statement for the June 1, 2005                    Distribution Date filed on Form 8-K on June 15, 2005.               7.    Trustee's Distribution Statement for the July 1, 2005                    Distribution Date filed on Form 8-K on July 13, 2005.               8.    Trustee's Distribution Statement for the August 1, 2005                    Distribution Date filed on Form 8-K on August 16, 2005.                   9.    Trustee's Distribution Statement for the September 1, 2005                    Distribution Date filed on Form 8-K on September 13, 2005.              10.    Trustee's Distribution Statement for the October 1, 2005                    Distribution Date filed on Form 8-K on 10. October 17, 2005.              11.    Trustee's Distribution Statement for the November 1, 2005                    Distribution Date filed on Form 8-K on 11. November 15, 2005.              12.    Trustee's Distribution Statement for the December 1, 2005                    Distribution Date filed on Form 8-K on 12. December 14, 2005.  (c)     See item 15(a)(3) above.                                        SIGNATURES                      Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.                                   Structured Products Corp., as depositor for the                                  Trust (the "Registrant")     Dated:  March 24, 2006              By:   /S/ MARK C. GRAHAM                                        ---------------------                                     Name:    Mark C. Graham                                     Title:   Assistant Secretary, Assistant Vice                                              President and Finance Officer                                                                          Exhibit 31.1                                    CERTIFICATION   I, Mark C. Graham, certify that:  1.          I have reviewed this annual report on Form 10-K, and all reports on Form 8-K containing distribution or servicing reports filed in respect of periods included in the year covered by this annual report, of Structured Products Corp., on behalf of CAST Step-Up Trust For Morgan Stanley Notes;  2.          Based on my knowledge, the information in these reports, taken as a whole, does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading as of the last day of the period covered by this annual report;  3.          Based on my knowledge, the distribution or servicing information required to be provided to the depositor by the trustee under the pooling and servicing, or similar agreement, for inclusion in these reports is included in these reports;  4.          I am responsible for reviewing the activities performed by the depositor and the trustee under the pooling and servicing, or similar agreement and based upon my knowledge and the annual compliance review required under that agreement, and except as disclosed in the reports, the depositor and trustee have each fulfilled its obligations under that agreement; and  5.          The reports disclose all significant deficiencies relating to the compliance by the trustee and the depositor with the minimum servicing or similar standards based upon the report provided by an independent public accountant, after conducting a review in compliance with the Uniform Single Attestation Program for Mortgage Bankers or similar procedure, as set forth in the pooling and servicing, or similar agreement, that is included in these reports.  In giving the certifications above, I have reasonably relied on information provided to me by the following unaffiliated parties: U.S. Bank Trust National Association.                                       By:     /S/ MARK C. GRAHAM                                        ---------------------------------                                     Name:   Mark C. Graham                                     Title:   Assistant Secretary, Assistant Vice                                              President and Finance Officer                                      Date:  March 24, 2006                                                                          Exhibit 99.1                                ANNUAL COMPLIANCE REPORT           The undersigned, being an officer of U.S. Bank Trust National Association, as trustee (the "Trustee"), with respect to CAST Step-Up Trust For Morgan Stanley Notes, listed in Structured Products Corp.'s annual report on Form 10-K for the fiscal year ended December 31, 2005 (the "Annual Report"), certifies as follows:  1.       The Trustee is the trustee under the trust agreement.  2.       Based on my knowledge, for the periods included in the year covered by the Annual Report, the Trustee has fulfilled its obligations, including any servicing obligations, under the trust agreement.                                                /S/ MARLENE FAHEY                                     -------------------------                                     Name:   Marlene Fahey                                     Title:  Vice President                                     Date:   March 24, 2006                                                                          Exhibit 99.2                           INDEPENDENT ACCOUNTANT'S REPORT             Structured Products Corp., as Depositor           388 Greenwich Street, 10th Floor           New York, New York 10013            U.S. Bank Trust National Association, as Trustee           Corporate Trust Department           100 Wall Street           New York, NY 10005            Re:    CAST Step-Up Trust for Morgan Stanley Notes (the                  "Trust")           Ladies and Gentlemen:            We have examined management's assertions that the Depositor and the           Trustee have complied, in all material respects, with the provisions           of the Base Trust Agreement dated as of December 15, 2000, as           supplemented by the CAST Step-Up Trust for Morgan Stanley Notes Series           Supplement, dated as of July 25, 2003 (together, the "Trust           Agreement"), during the period covered by the annual report on Form           10-K filed by the Depositor on behalf of the Trust for the year ended           December 31, 2005 (the "Annual Report"). Management is responsible for           compliance with the Trust Agreement. Our responsibility is to express           an opinion on management's assertions based on our examination.            Our examination was made in accordance with standards established by           the American Institute of Certified Public Accountants and,           accordingly, included examining, on a test basis, evidence about the           Depositor's and the Trustee's compliance with the Trust Agreement and           performing such other procedures as considered necessary in the           circumstances. We believe that our examination provides a reasonable           basis for our opinion.            In our opinion, the Depositor and the Trustee have complied, in all           material respects, with the Trust Agreement during the period covered           by the Annual Report and management's assertions with respect to such           compliance are fairly stated, in all material respects, for the year           ended December 31, 2005.              New York, New York           March 21, 2006                                       EXHIBIT INDEX     Exhibit                                                                  Page     31.1     Certification by Assistant Secretary, Assistant Vice              President and Finance Officer of the Registrant pursuant              to 15 U.S.C. Section 7241, as adopted pursuant to Section              302 of the Sarbanes-Oxley Act of 2002.      99.1     Annual Compliance Report by Trustee pursuant to 15 U.S.C.              Section 7241.      99.2     Report of Aston Bell & Associates.    -----END PRIVACY-ENHANCED MESSAGE-----