SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549

                                   FORM 10-K

                ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d)
                    OF THE SECURITIES EXCHANGE ACT OF 1934

       For the fiscal year ended:               Commission File Number:
            December 31, 2004                          001-31677

                           STRUCTURED PRODUCTS CORP.,
                                  on behalf of

                    CAST Step-Up Trust For Dow Chemical Notes

            (Exact name of registrant as specified in its charter)

           Delaware                                    13-3692801
        (State or other                             (I.R.S. Employer
        jurisdiction of                           Identification No.)
       incorporation or
         organization)

                              388 Greenwich Street
                            New York, New York 10013
                        (Address of principal executive
                              offices) (zip code)

Registrant's telephone number including area code:

                                 212-816-7496

Securities registered pursuant to Section 12(b) of the Act:

           Title of Each Class                 Name of Each Exchange on Which
                                                         Registered

CAST Step-Up Trust For Dow Chemical              New York Stock Exchange
Notes, Monthly-Pay Step-Up Class A
Certificates

Securities registered pursuant to Section 12(g) of the Act:

                                     None

Indicate by check mark whether the Registrant has (1) filed all reports required
to be filed by section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the Registrant was
required to have filed such reports) and (2) has been subject to such filing
requirements for the past 90 days.

                                Yes X(1)      No
                                    ----        ----

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of Registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K. [ ]

------------------
(1) Pursuant to staff administrative positions established in the no-action
letter Corporate Asset Backed Corporation ("CABCO") (available August 9, 1995),
the Depositor is not required to respond to various items of Form 10-K. Such
items are designated herein as "Not Applicable".


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As of the date of this report, all of the common stock of the Registrant is held
by Citigroup Global Markets Holdings Inc.

Indicate by check mark whether the Registrant is an accelerated filer (as
defined in Exchange Act Rule 12b-2).

                                Yes       No X
                                   ---      ---

                       Documents Incorporated by Reference

The distribution reports to security holders filed on Form 8-K during the fiscal
year in lieu of reports on Form 10-Q, which includes the reports filed on Form
8-K listed in Item 15(b) hereto.

                                Introductory Note

Structured Products Corp. (the "Depositor") is the depositor under the Base
Trust Agreement, dated as of December 15, 2000, as supplemented by the CAST
Supplement 2003-4, dated as of April 22, 2003, by and between the Depositor and
U.S. Bank Trust National Association, as Trustee (the "Trustee"), providing for
the issuance of the CAST Step-Up Trust For Dow Chemical Notes, Monthly-Pay
Step-Up Class A Certificates (the "Certificates") and is the depositor for the
Certificates (the "Registrant"). The Certificates do not represent obligations
of or interests in the Depositor or the Trustee.

The issuer(s) of the underlying securities, or guarantor thereof, or successor
thereto, as applicable, is subject to the information reporting requirements of
the Securities Exchange Act of 1934, as amended (the "Exchange Act"). For
information on the issuer(s) of the underlying securities, or guarantor thereof,
or successor thereto, as applicable, please see its periodic and current reports
filed with the Securities and Exchange Commission (the "Commission"). Such
reports and other information required to be filed pursuant to the Exchange Act,
by the issuer(s) of the underlying securities, or guarantor thereof, or
successor thereto, as applicable, may be inspected and copied at the public
reference facilities maintained by the Commission at 450 Fifth Street, N.W.,
Washington, D.C. 20549. The Commission also maintains a site on the World Wide
Web at "http://www.sec.gov" at which users can view and download copies of
reports, proxy and information statements and other information filed
electronically through the Electronic Data Gathering, Analysis and Retrieval
system, or "EDGAR." Neither the Depositor nor the Trustee has participated in
the preparation of such reporting documents, or made any due diligence
investigation with respect to the information provided therein. Neither the
Depositor nor the Trustee has verified the accuracy or completeness of such
documents or reports. There can be no assurance that events affecting the
issuer(s) of the underlying securities, or guarantor thereof, or successor
thereto, as applicable, or the underlying securities have not occurred or have
not yet been publicly disclosed that would affect the accuracy or completeness
of the publicly available documents described above. The chart below lists each
trust, the issuer(s) or guarantor, or successor thereto, of the related
underlying security, and its respective Exchange Act file numbers, if
applicable.

               Underlying Securities Issuer(s)   Exchange Act File
                 or Guarantor, or successor            Number
                           thereto
              -------------------------------------------------------
                  The Dow Chemical Company           001-03433



<PAGE>


                                     PART I

Item 1.  Business

         None

Item 2.  Properties

         None

Item 3.  Legal Proceedings

         None

Item 4.  Submission of Matters To A Vote of Security Holders

         None

                                     PART II

Item 5.  Market for Registrant's Common Equity and Related Stockholder Matters

         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.

Item 6.  Selected Financial Data

         None

Item 7.  Management's Discussion and Analysis of Financial Condition and
         Results of Operations

         Not Applicable

Item 7A. Quantitative and Qualitative Disclosures About Market Risk

         None

Item 8.  Financial Statements and Supplementary Data

         None

Item 9.  Changes In and Disagreements With Accountants on Accounting and
         Financial Disclosure

         None

Item 9A. Controls and Procedures

         Not Applicable

Item 9B. Other Information

         None

                                    PART III

Item 10. Directors and Executive Officers of the Registrant

         None


<PAGE>

Item 11. Executive Compensation

         Not Applicable

Item 12.  Security Ownership of Certain Beneficial Owners and Management

         Information required by Item 201(d) of Regulation S-X: Not applicable

         Information required by Item 403 of Regulation S-X:  None

Item 13. Certain Relationships and Related Transactions

         None

Item 14. Principal Accounting Fees and Services

         Not Applicable

                                     PART IV

Item 15. Exhibits, Financial Schedules and Reports on Form 8-K

(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.

(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, 2004
              Distribution Date filed on Form 8-K on January 13, 2004.

          2.  Trustee's Distribution Statement for the February 1, 2004
              Distribution Date filed on Form 8-K on February 11, 2004.

          3.  Trustee's Distribution Statement for the March 1, 2004
              Distribution Date filed on Form 8-K on March 11, 2004.

          4.  Trustee's Distribution Statement for the April 1, 2004
              Distribution Date filed on Form 8-K on April 13, 2004.

          5.  Trustee's Distribution Statement for the May 1, 2004 Distribution
              Date filed on Form 8-K on May 12, 2004.

          6.  Trustee's Distribution Statement for the June 1, 2004 Distribution
              Date filed on Form 8-K on June 10, 2004.

          7.  Trustee's Distribution Statement for the July 1, 2004 Distribution
              Date filed on Form 8-K on July 15, 2004.

          8.  Trustee's Distribution Statement for the August 1, 2004
              Distribution Date filed on Form 8-K on August 10, 2004.

          9.  Trustee's Distribution Statement for the September 1, 2004
              Distribution Date filed on Form 8-K on September 14, 2004.

          10.  Trustee's Distribution Statement for the October 1, 2004
               Distribution 10. Date filed on Form 8-K on October 14, 2004.

          11.  Trustee's Distribution Statement for the November 1, 2004
               Distribution Date filed on Form 8-K on November 10, 2004.

          12.  Trustee's Distribution Statement for the December 1, 2004
               Distribution Date filed on Form 8-K on December 15, 2004.

(c) See item 15(a)(3) above.



<PAGE>



                                  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, 2005            By:           /s/ Mark C. Graham
                                    --------------------------------------------
                                 Name:  Mark C. Graham
                                 Title: Assistant Secretary, Assistant Vice
                                        President and Finance Officer



<PAGE>


                                                                    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 Dow Chemical 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;
and

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.

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, 2005


<PAGE>


                                                                    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 Dow Chemical
Notes, on whose behalf Structured Products Corp. has prepared this annual report
on Form 10-K for the fiscal year ended December 31, 2004 (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, 2005



<PAGE>



                                 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.