<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): March 1, 2006

                         MERRILL LYNCH DEPOSITOR, INC.
             (ON BEHALF OF PUBLIC STEERS SERIES 1999 REN-C1 TRUST)
             (Exact name of registrant as specified in its charter)


        DELAWARE                   001-15485                  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


Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2.):

[  ]  Written communications pursuant to Rule 425 under the Securities Act
      (17 CFR 230.425)

[  ]  Soliciting material pursuant to Rule 14a-12 under the Exchange Act
      (17 CFR 240.14a-12)

[  ]  Pre-commencement communications pursuant to Rule 14d-2(b) under the
      Exchange Act (17 CFR 240.14d-2(b))

[  ]  Pre-commencement communications pursuant to Rule 13e-4(c) under the
      Exchange Act (17 CFR 240.13e-4(c))


<PAGE>

                      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 PublicSTEERS
                           Trust Series 1999 REN-C1 Certificates on March 1,
                           2006.

                           For information with respect to the underlying
                  securities held by Public STEERS Trust Series REN-C1, please
                  refer to RenaissanceRe Holdings Ltd.'s (Commission file number
                  001-14428) 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 and the underlying securities
                  issuer has filed electronically with the SEC.


<PAGE>

                           Although we have no reason to believe the information
                  concerning the underlying securities, the junior subordinated
                  debentures, the underlying securities issuer or the underlying
                  securities guarantor contained in the prospectus related to
                  the underlying securities or 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
                  junior subordinated debentures 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 the junior
                  subordinated debentures 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 junior subordinated debentures, 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.

                  (c) Exhibits.

                      99.1.    Trustee's report in respect of the March 1,
                               2006 distribution to holders of the Public
                               STEERS Trust Series 1999 REN-C1 Certificates.


<PAGE>

                                   SIGNATURES

Pursuant to the requirements of Section 12 of the Securities Exchange Act of
1934, the registrant has duly caused this report to be signed on its behalf by
the undersigned, thereto duly authorized.


                                       MERRILL LYNCH DEPOSITOR, INC.

Date: March 10, 2006                   By:      /s/ Stephan Kuppenheimer
                                                 ------------------------------
                                       Name:    Stephan Kuppenheimer
                                       Title:   President


<PAGE>

                                  EXHIBIT INDEX


99.1.    Trustee's report in respect of the March 1, 2006 distribution to
         holders of the Public STEERS Trust Series 1999 REN-C1 Certificates.
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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): March 1, 2006

                         MERRILL LYNCH DEPOSITOR, INC.
             (ON BEHALF OF PUBLIC STEERS SERIES 1999 REN-C1 TRUST)
             (Exact name of registrant as specified in its charter)

        DELAWARE                   001-15485                  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

Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2.):

[  ]  Written communications pursuant to Rule 425 under the Securities Act
      (17 CFR 230.425)

[  ]  Soliciting material pursuant to Rule 14a-12 under the Exchange Act
      (17 CFR 240.14a-12)

[  ]  Pre-commencement communications pursuant to Rule 14d-2(b) under the
      Exchange Act (17 CFR 240.14d-2(b))

[  ]  Pre-commencement communications pursuant to Rule 13e-4(c) under the
      Exchange Act (17 CFR 240.13e-4(c))
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 PublicSTEERS
                           Trust Series 1999 REN-C1 Certificates on March 1,
                           2006.

                           For information with respect to the underlying
                  securities held by Public STEERS Trust Series REN-C1, please
                  refer to RenaissanceRe Holdings Ltd.'s (Commission file number
                  001-14428) 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 and the underlying securities
                  issuer has filed electronically with the SEC.
Although we have no reason to believe the information
                  concerning the underlying securities, the junior subordinated
                  debentures, the underlying securities issuer or the underlying
                  securities guarantor contained in the prospectus related to
                  the underlying securities or 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
                  junior subordinated debentures 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 the junior
                  subordinated debentures 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 junior subordinated debentures, 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.

                  (c) Exhibits.

                      99.1.    Trustee's report in respect of the March 1,
                               2006 distribution to holders of the Public
                               STEERS Trust Series 1999 REN-C1 Certificates.
SIGNATURES

Pursuant to the requirements of Section 12 of the Securities Exchange Act of
1934, the registrant has duly caused this report to be signed on its behalf by
the undersigned, thereto duly authorized.

                                       MERRILL LYNCH DEPOSITOR, INC.

Date: March 10, 2006                   By:      /s/ Stephan Kuppenheimer
                                                 ------------------------------
                                       Name:    Stephan Kuppenheimer
                                       Title:   President
EXHIBIT INDEX

99.1.    Trustee's report in respect of the March 1, 2006 distribution to
         holders of the Public STEERS Trust Series 1999 REN-C1 Certificates.