<PAGE>

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D. C. 20549
                           --------------------------

                                    FORM 8-K

                                 CURRENT REPORT

                       Pursuant to Section 13 or 15(d) of
                       The Securities Exchange Act of 1934
                            -------------------------

       Date of Report (Date of earliest event reported): December 20, 2005

                          MERRILL LYNCH DEPOSITOR, INC.
                  (ON BEHALF OF INDEXPLUS TRUST SERIES 2003-1)
             (Exact name of registrant as specified in its charter)

            DELAWARE             001-31941                    13-3891329
        (State or other        (Commission                (I. R. S. Employer
        jurisdiction  of        File Number)              Identification No.)
         incorporation)

     WORLD FINANCIAL CENTER,                                     10080
       NEW YORK, NEW YORK                                     (Zip Code)
      (Address of principal
       executive offices)
                           --------------------------

       Registrant's telephone number, including area code: (212) 449-1000

                      INFORMATION TO BE INCLUDED IN REPORT


SECTION 1.        REGISTRANT'S BUSINESS AND OPERATIONS

                  Not applicable.

SECTION 2.        FINANCIAL INFORMATION

                  Not applicable.

SECTION 3.        SECURITIES AND TRADING MARKETS

                  Not applicable.

SECTION 4.        MATTERS RELATED TO ACCOUNTANTS AND FINANCIAL STATEMENTS

                  Not applicable.

SECTION 5.        CORPORATE GOVERNANCE AND MANAGEMENT

                  Not applicable.

SECTION 6.        ASSET-BACKED SECURITIES

                  Not applicable.


<PAGE>

SECTION 7.        REGULATION FD

                  Not applicable.

SECTION 8.        OTHER EVENTS

         ITEM 8.01    OTHER EVENTS

              99.1    Distribution to holders of the INDEXPLUS Trust
                      Certificates Series 2003-1 on December 20, 2005.

                          For information with respect to the underlying
                      securities held by INDEXPLUS Trust Series 2003-1, please
                      refer to the respective periodic reports, including annual
                      reports on Form 10-K, quarterly reports on Form 10-Q,
                      current reports on Form 8-K and other information on file
                      with the Securities and Exchange Commission (the "SEC")
                      of: The Boeing Company (Commission file number 001-00442);
                      Citigroup Inc. (Commission file number 001-09924); Credit
                      Suisse First Boston (USA), Inc. (Commission file number
                      001-06862); DaimlerChrysler North America Holding
                      Corporation (Commission file number 333-13160);
                      DaimlerChrysler AG (Commission file number 001-14561);
                      Ford Motor Company (Commission file number 001-03950);
                      General Electric Capital Corporation (Commission file
                      number 001-06461); General Motors Acceptance Corporation
                      (Commission file number 001-03754); The Goldman Sachs
                      Group, Inc. (Commission file number 001-14965); Johnson &
                      Johnson (Commission file number 001-03215); Federated
                      Retail Holdings, Inc. (Commission file number 333-42940);
                      The May Department Stores Company, LLC (Commission file
                      number 001-00079); Time Warner Inc. (Commission file
                      number 001-15062); Time Warner Companies, Inc. (Commission
                      file number 001-08637); Turner Broadcasting System, Inc.
                      (Commission file number 001-08911); United States
                      Department of Treasury; Valero Energy Corporation
                      (Commission file number 001-13175); Verizon Communications
                      Inc. (Commission file number 001-08606); Verizon Global
                      Funding Corp. (Commission file number 333-73612); Viacom
                      Inc. (Commission file number 001-09553); Viacom
                      International Inc. (Commission file number 001-15153) and
                      Weyerhaeuser Company (Commission file number 001-04825).
                      You can read and copy these reports and other information
                      at the public reference facilities maintained by the SEC
                      at Room 1580, 100 F Street, NE, Washington, D.C. 20549.
                      You may obtain copies of this material for a fee by
                      writing to the SEC's Public Reference Section of the SEC
                      at 100 F Street, NE, Washington, D.C. 20549. You may
                      obtain information about the operation of the Public
                      Reference Room by calling the SEC at 1-800-SEC-0330. You
                      can also access some of this information electronically by
                      means of the SEC's website on the Internet at
                      http://www.sec.gov, which contains reports, proxy and
                      information statements and other information that the
                      respective underlying securities issuers have filed
                      electronically with the SEC.


<PAGE>

                          Although we have no reason to believe the information
                      concerning the underlying securities or the underlying
                      securities issuers contained in the underlying securities
                      issuers' Exchange Act reports is not reliable, neither the
                      depositor nor the trustee participated in the preparation
                      of such documents or made any due diligence inquiry with
                      respect to the information provided therein. No
                      investigation with respect to the underlying securities
                      issuers (including, without limitation, no investigation
                      as to their financial condition or creditworthiness) or of
                      the underlying securities has been made. You should obtain
                      and evaluate the same information concerning the
                      respective underlying securities issuers as you would
                      obtain and evaluate if you were investing directly in the
                      respective underlying securities or in other securities
                      issued by the respective underlying securities issuers.
                      There can be no assurance that events affecting the
                      respective underlying securities or the respective
                      underlying securities issuers have not occurred or have
                      not yet been publicly disclosed which would affect the
                      accuracy or completeness of the publicly available
                      documents described above.

SECTION 9.        FINANCIAL STATEMENTS AND EXHIBITS

         ITEM 9.01    FINANCIAL STATEMENTS AND EXHIBITS

                (a)   Financial statements of business acquired.

                      Not applicable.

                (b)   Pro forma financial information.

                      Not applicable.

                (c)   Shell company transactions.

                      Not applicable

                (d)   Exhibits.

                      99.1   Trustee's report in respect of the December 20,
                             2005 distribution to holders of the INDEXPLUS Trust
                             Certificates Series 2003-1.









<PAGE>


                                   SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned, hereunto duly authorized.


                                            MERRILL LYNCH DEPOSITOR, INC.

Date: December 29, 2005                     By:      /s/ Zvi Gillon
                                                     ---------------------------
                                            Name:    Zvi Gillon
                                            Title:   Vice President











<PAGE>

                                  EXHIBIT INDEX


99.1     Trustee's report in respect of the December 20, 2005 distribution to
         holders of the INDEXPLUS Trust Certificates Series 2003-1.
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SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D. C. 20549
                           --------------------------

                                    FORM 8-K

                                 CURRENT REPORT

                       Pursuant to Section 13 or 15(d) of
                       The Securities Exchange Act of 1934
                            -------------------------

       Date of Report (Date of earliest event reported): December 20, 2005

                          MERRILL LYNCH DEPOSITOR, INC.
                  (ON BEHALF OF INDEXPLUS TRUST SERIES 2003-1)
             (Exact name of registrant as specified in its charter)

            DELAWARE             001-31941                    13-3891329
        (State or other        (Commission                (I. R. S. Employer
        jurisdiction  of        File Number)              Identification No.)
         incorporation)

     WORLD FINANCIAL CENTER,                                     10080
       NEW YORK, NEW YORK                                     (Zip Code)
      (Address of principal
       executive offices)
                           --------------------------

       Registrant's telephone number, including area code: (212) 449-1000

                      INFORMATION TO BE INCLUDED IN REPORT

SECTION 1.        REGISTRANT'S BUSINESS AND OPERATIONS

                  Not applicable.

SECTION 2.        FINANCIAL INFORMATION

                  Not applicable.

SECTION 3.        SECURITIES AND TRADING MARKETS

                  Not applicable.

SECTION 4.        MATTERS RELATED TO ACCOUNTANTS AND FINANCIAL STATEMENTS

                  Not applicable.

SECTION 5.        CORPORATE GOVERNANCE AND MANAGEMENT

                  Not applicable.

SECTION 6.        ASSET-BACKED SECURITIES

                  Not applicable.
SECTION 7.        REGULATION FD

                  Not applicable.

SECTION 8.        OTHER EVENTS

         ITEM 8.01    OTHER EVENTS

              99.1    Distribution to holders of the INDEXPLUS Trust
                      Certificates Series 2003-1 on December 20, 2005.

                          For information with respect to the underlying
                      securities held by INDEXPLUS Trust Series 2003-1, please
                      refer to the respective periodic reports, including annual
                      reports on Form 10-K, quarterly reports on Form 10-Q,
                      current reports on Form 8-K and other information on file
                      with the Securities and Exchange Commission (the "SEC")
                      of: The Boeing Company (Commission file number 001-00442);
                      Citigroup Inc. (Commission file number 001-09924); Credit
                      Suisse First Boston (USA), Inc. (Commission file number
                      001-06862); DaimlerChrysler North America Holding
                      Corporation (Commission file number 333-13160);
                      DaimlerChrysler AG (Commission file number 001-14561);
                      Ford Motor Company (Commission file number 001-03950);
                      General Electric Capital Corporation (Commission file
                      number 001-06461); General Motors Acceptance Corporation
                      (Commission file number 001-03754); The Goldman Sachs
                      Group, Inc. (Commission file number 001-14965); Johnson &
                      Johnson (Commission file number 001-03215); Federated
                      Retail Holdings, Inc. (Commission file number 333-42940);
                      The May Department Stores Company, LLC (Commission file
                      number 001-00079); Time Warner Inc. (Commission file
                      number 001-15062); Time Warner Companies, Inc. (Commission
                      file number 001-08637); Turner Broadcasting System, Inc.
                      (Commission file number 001-08911); United States
                      Department of Treasury; Valero Energy Corporation
                      (Commission file number 001-13175); Verizon Communications
                      Inc. (Commission file number 001-08606); Verizon Global
                      Funding Corp. (Commission file number 333-73612); Viacom
                      Inc. (Commission file number 001-09553); Viacom
                      International Inc. (Commission file number 001-15153) and
                      Weyerhaeuser Company (Commission file number 001-04825).
                      You can read and copy these reports and other information
                      at the public reference facilities maintained by the SEC
                      at Room 1580, 100 F Street, NE, Washington, D.C. 20549.
                      You may obtain copies of this material for a fee by
                      writing to the SEC's Public Reference Section of the SEC
                      at 100 F Street, NE, Washington, D.C. 20549. You may
                      obtain information about the operation of the Public
                      Reference Room by calling the SEC at 1-800-SEC-0330. You
                      can also access some of this information electronically by
                      means of the SEC's website on the Internet at
                      http://www.sec.gov, which contains reports, proxy and
                      information statements and other information that the
                      respective underlying securities issuers have filed
                      electronically with the SEC.
Although we have no reason to believe the information
                      concerning the underlying securities or the underlying
                      securities issuers contained in the underlying securities
                      issuers' Exchange Act reports is not reliable, neither the
                      depositor nor the trustee participated in the preparation
                      of such documents or made any due diligence inquiry with
                      respect to the information provided therein. No
                      investigation with respect to the underlying securities
                      issuers (including, without limitation, no investigation
                      as to their financial condition or creditworthiness) or of
                      the underlying securities has been made. You should obtain
                      and evaluate the same information concerning the
                      respective underlying securities issuers as you would
                      obtain and evaluate if you were investing directly in the
                      respective underlying securities or in other securities
                      issued by the respective underlying securities issuers.
                      There can be no assurance that events affecting the
                      respective underlying securities or the respective
                      underlying securities issuers have not occurred or have
                      not yet been publicly disclosed which would affect the
                      accuracy or completeness of the publicly available
                      documents described above.

SECTION 9.        FINANCIAL STATEMENTS AND EXHIBITS

         ITEM 9.01    FINANCIAL STATEMENTS AND EXHIBITS

                (a)   Financial statements of business acquired.

                      Not applicable.

                (b)   Pro forma financial information.

                      Not applicable.

                (c)   Shell company transactions.

                      Not applicable

                (d)   Exhibits.

                      99.1   Trustee's report in respect of the December 20,
                             2005 distribution to holders of the INDEXPLUS Trust
                             Certificates Series 2003-1.
SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned, hereunto duly authorized.

                                            MERRILL LYNCH DEPOSITOR, INC.

Date: December 29, 2005                     By:      /s/ Zvi Gillon
                                                     ---------------------------
                                            Name:    Zvi Gillon
                                            Title:   Vice President
EXHIBIT INDEX

99.1     Trustee's report in respect of the December 20, 2005 distribution to
         holders of the INDEXPLUS Trust Certificates Series 2003-1.