<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 1, 2005

                          MERRILL LYNCH DEPOSITOR, INC.
       (ON BEHALF OF PREFERREDPLUS 7.30% TRUST CERTIFICATES SERIES BLS-1)
             (Exact name of registrant as specified in its charter)

         DELAWARE             001-16471                    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.
<PAGE>

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 PreferredPLUS 7.30%
                           Trust Certificates Series BLS-1 on December 1, 2005.

                                    For information with respect to the
                           underlying securities held by PreferredPLUS Trust
                           Series BLS-1, please refer to BellSouth Corporation's
                           (Commission file number 001-08607) periodic reports,
                           including annual reports on Form 10-K, quarterly
                           reports on Form 10-Q and current reports on Form 8-K,
                           and other information on file with the Securities and
                           Exchange Commission (the "SEC"). 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 underlying securities
                           guarantor has filed electronically with the SEC.

                                    Although we have no reason to believe the
                           information concerning the underlying securities, the
                           guarantee, the underlying securities issuer or the
                           underlying securities guarantor contained in the
                           underlying securities guarantor's 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 issuer or the underlying securities
                           guarantor (including, without limitation, no
                           investigation as to their respective financial
                           condition or creditworthiness) or of the underlying
                           securities or the guarantee has been made. You should
                           obtain and evaluate the same information concerning
                           the underlying securities issuer and the underlying
                           securities guarantor as you would obtain and evaluate
                           if you were investing directly in the underlying
                           securities or in other securities issued by the
                           underlying securities issuer or the underlying
                           securities guarantor. There can be no assurance that
                           events affecting the underlying securities, the
                           guarantee, the underlying securities issuer or the
                           underlying securities guarantor have not occurred or
                           have not yet been publicly disclosed which would
                           affect the accuracy or completeness of the publicly
                           available documents described above.

<PAGE>

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 1, 2005
                        distribution to holders of the PreferredPLUS 7.30%
                        Trust Certificates Series BLS-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 8, 2005         By:    /s/ Stephan Kuppenheimer
                                                ------------------------------
                                        Name:  Stephan Kuppenheimer
                                        Title: President

<PAGE>



                                  EXHIBIT INDEX


                   99.1   Trustee's report in respect of the December 1, 2005
                          distribution to holders of the PreferredPLUS 7.30%
                          Trust Certificates Series BLS-1.
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{"company-data": {"conformed-name": "MERRILL LYNCH DEPOSITOR INC PREFERREDPLUS TRUST SERIES BLS-1", "cik": "0001139349", "assigned-sic": "6189", "irs-number": "133891329", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "001-16471", "film-number": "051252469"}, "business-address": {"street1": "WORLD FINANCIAL CENTER", "city": "NEW YORK", "state": "NY", "zip": "10281", "phone": "2124491000"}, "mail-address": {"street1": "WORLD FINANCIAL CTR", "street2": "NORTH TOWER", "city": "NEW YORK", "state": "NY", "zip": "10281"}}
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 1, 2005

                          MERRILL LYNCH DEPOSITOR, INC.
       (ON BEHALF OF PREFERREDPLUS 7.30% TRUST CERTIFICATES SERIES BLS-1)
             (Exact name of registrant as specified in its charter)

         DELAWARE             001-16471                    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 PreferredPLUS 7.30%
                           Trust Certificates Series BLS-1 on December 1, 2005.

                                    For information with respect to the
                           underlying securities held by PreferredPLUS Trust
                           Series BLS-1, please refer to BellSouth Corporation's
                           (Commission file number 001-08607) periodic reports,
                           including annual reports on Form 10-K, quarterly
                           reports on Form 10-Q and current reports on Form 8-K,
                           and other information on file with the Securities and
                           Exchange Commission (the "SEC"). 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 underlying securities
                           guarantor has filed electronically with the SEC.

                                    Although we have no reason to believe the
                           information concerning the underlying securities, the
                           guarantee, the underlying securities issuer or the
                           underlying securities guarantor contained in the
                           underlying securities guarantor's 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 issuer or the underlying securities
                           guarantor (including, without limitation, no
                           investigation as to their respective financial
                           condition or creditworthiness) or of the underlying
                           securities or the guarantee has been made. You should
                           obtain and evaluate the same information concerning
                           the underlying securities issuer and the underlying
                           securities guarantor as you would obtain and evaluate
                           if you were investing directly in the underlying
                           securities or in other securities issued by the
                           underlying securities issuer or the underlying
                           securities guarantor. There can be no assurance that
                           events affecting the underlying securities, the
                           guarantee, the underlying securities issuer or the
                           underlying securities guarantor 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 1, 2005
                        distribution to holders of the PreferredPLUS 7.30%
                        Trust Certificates Series BLS-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 8, 2005         By:    /s/ Stephan Kuppenheimer
                                                ------------------------------
                                        Name:  Stephan Kuppenheimer
                                        Title: President
EXHIBIT INDEX

                   99.1   Trustee's report in respect of the December 1, 2005
                          distribution to holders of the PreferredPLUS 7.30%
                          Trust Certificates Series BLS-1.