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    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">UNITED
      STATES</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">SECURITIES
      AND EXCHANGE COMMISSION</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Washington,
      D.C. 20549</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">FORM
      8-K</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">CURRENT
      REPORT</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">PURSUANT
      TO SECTION 13 OR 15(d) OF THE</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">SECURITIES
      EXCHANGE ACT OF 1934</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Date
      of
      Report (Date of earliest event reported)</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">February
      28, 2006</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">STRUCTURED
      ASSET SECURITIES CORPORATION (as Depositor under the Trust Agreement dated
      as of
      February 1, 2006, providing for the issuance of Structured Asset Securities
      Corporation Mortgage Pass-Through Certificates, Series 2006-S1)</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><u>&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;Structured
      Asset Securities Corporation&#160;Mortgage Loan Trust
      2006-S1&#160;&#160;&#160;&#160;&#160;&#160;&#160;</u></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(Exact
      Name of Issuing Entity as Specified in its Charter)</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><u>&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;Structured
      Asset Securities
      Corporation&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</u></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(Exact
      Name of Depositor as Specified in its Charter)</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><u>&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;Lehman
      Brothers Holdings
      Inc.&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</u></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(Exact
      Name of Sponsor as Specified in its Charter)</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><u>&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;Structured
      Asset Securities
      Corporation&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</u></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(Exact
      Name of Registrant as Specified in its Charter)</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
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              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;<u>&#160;</u></font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><u>Delaware&#160;</u></font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</font></div>
            </td>
            <td valign="top" width="24%" style="border-bottom: medium none;">
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            </td>
            <td valign="top" width="24%" style="border-bottom: medium none;">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">&#160;&#160;<u>&#160;&#160;</u></font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><u>74-2440850</u>&#160;</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">&#160;&#160;&#160;</font></div>
            </td>
          </tr>
          <tr>
            <td valign="top" width="24%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(State
                or Other Jurisdiction</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Of
                Incorporation)</font></div>
            </td>
            <td valign="top" width="24%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(Commission</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">File
                Number)</font></div>
            </td>
            <td valign="top" width="24%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(I.R.S.
                Employer</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Identification
                No.)</font></div>
            </td>
          </tr>

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    </div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div>
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              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">745
                Seventh Avenue, 7</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><sup>th</sup></font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">
                Floor</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><u>New
                York, NY</u></font></div>
            </td>
            <td align="left" valign="top" width="24%" style="border-bottom: medium none;">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="24%" style="border-bottom: medium none;">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><u><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">10019</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY: Times New Roman">&#160;</font></u></div>
            </td>
          </tr>
          <tr>
            <td valign="top" width="24%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(Address
                of Principal Executive Offices)</font></div>
            </td>
            <td align="left" valign="top" width="24%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td valign="top" width="24%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(Zip
                Code)</font></div>
            </td>
          </tr>

      </table>
    </div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Registrant&#8217;s
      telephone number, including area code: (212) 526-7000</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><u>&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;
      No
      Change&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</u></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(Former
      Name or Former Address, if Changed Since Last Report)</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">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:</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Wingdings">o</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">&#160;Written
      communications pursuant to Rule 425 under the Securities Act (17 CFR
      230.425)</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Wingdings">o</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">&#160;Soliciting
      material pursuant to Rule 14a-12 under the Exchange Act (17 CFR
      240.14a-12)</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Wingdings">o</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">&#160;Pre-commencement
      communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR
      240.14d-2(b))</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Wingdings">o</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">&#160;Pre-commencement
      communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR
      240.13e-4(c))&#160;</font></div>
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    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Item
      8.01.&#160;&#160;</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><u>Other
      Events</u></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 36pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">The
      Registrant registered the issuance of Structured Asset Securities Corporation
      Mortgage Pass-Through Certificates, Series 2006-S1 on a delayed or continuous
      basis pursuant to Rule 415 under the Securities Act of 1933, as amended (the
      &#8220;Act&#8221;), by a Registration Statement on Form S-3 (Registration File No.
      333-127589-38) (the &#8220;Registration Statement&#8221;). Pursuant to the Registration
      Statement, the Registrant issued $432,534,000 aggregate principal amount of
      Class A1, Class A2, Class M1, Class M2, Class M3, Class M4, Class M5, Class
      M6,
      Class M7 and Class M8 Certificates of its Structured Asset Securities
      Corporation Mortgage Pass-Through Certificates, Series 2006-S1 on February
      28,
      2006. This Current Report on Form 8-K is being filed to satisfy an undertaking,
      contained in the definitive Prospectus dated September 26, 2005, as supplemented
      by the Prospectus Supplement dated February 23, 2006 (the &#8220;Prospectus
      Supplement&#8221;), to file a copy of the Trust Agreement (as defined below) and other
      material operative agreements executed in connection with the issuance of the
      Certificates, a form of which was filed as an exhibit to the Registration
      Statement.</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 36pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">The
      Certificates were issued pursuant to a Trust Agreement (the &#8220;Trust Agreement&#8221;),
      attached hereto as </font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><u>Exhibit
      4.1</u></font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">,
      dated
      as of February 1, 2006, among Structured Asset Securities Corporation, as
      depositor, Aurora Loan Services LLC, as Master Servicer, and U.S. Bank National
      Association, as Trustee. The &#8220;Certificates&#8221; consist of the following classes:
      Class A1, Class A2, Class M1, Class M2, Class M3, Class M4, Class M5, Class
      M6,
      Class M7, Class M8, , Class B1, Class B2, Class P, Class X, Class R and Class
      LT-R. The Certificates evidence all of the beneficial ownership interest in
      a
      trust fund (the &#8220;Trust Fund&#8221;) that consists primarily of a pool of certain
      conventional, second lien, fixed rate, fully amortizing and balloon, residential
      mortgage loans, with an aggregate outstanding principal balance of $441,642,561
      as of February 1, 2006, together with certain other assets. Capitalized terms
      used herein and not otherwise defined shall have the meanings assigned to them
      in the Trust Agreement.</font></div>
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    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 72pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
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            <td align="left" colspan="4" valign="top" width="72%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Item
                9.01. Financial Statements and Exhibits</font></div>
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          <tr>
            <td align="left" colspan="4" valign="top" width="72%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td valign="top" width="4%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(a)</font></div>
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            <td align="left" colspan="2" valign="top" width="14%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Not
                applicable.</font></div>
            </td>
            <td align="left" valign="top" width="54%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="4%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" colspan="2" valign="top" width="14%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="54%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td valign="top" width="4%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(b)</font></div>
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            <td align="left" colspan="2" valign="top" width="14%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Not
                applicable.</font></div>
            </td>
            <td align="left" valign="top" width="54%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="4%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" colspan="2" valign="top" width="14%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="54%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td valign="top" width="4%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(c)</font></div>
            </td>
            <td align="left" colspan="2" valign="top" width="14%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Not
                applicable.</font></div>
            </td>
            <td align="left" valign="top" width="54%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="4%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" colspan="2" valign="top" width="14%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="54%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="4%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(d)</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" colspan="2" valign="top" width="14%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Exhibits:</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="54%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="4%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="7%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">4.1</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" colspan="2" valign="top" width="61%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Trust
                Agreement dated as of February 1, 2006, among Structured Asset Securities
                Corporation, as Depositor, Aurora Loan Services LLC, as Master Servicer,
                Clayton Fixed Income Services, Inc. as Credit Risk Manager, and U.S.
                Bank
                National Association, as Trustee.</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="4%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="7%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">99.1</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" colspan="2" valign="top" width="61%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Mortgage
                Loan Sale and Assignment Agreement dated as of February 1, 2006,
                between
                Lehman Brothers Holdings Inc., as Seller, and Structured Asset Securities
                Corporation, as Purchaser.</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="4%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="7%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">99.2</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" colspan="2" valign="top" width="61%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Servicing
                Agreement dated as of February 1, 2006, by and among Lehman Brothers
                Holdings Inc., as Seller, and Aurora Loan Services LLC, in the dual
                capacities of Servicer and Master Servicer.</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="4%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="7%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">99.3</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" colspan="2" valign="top" width="61%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Interest
                Rate Swap Agreement, dated as of February 28, 2006 (including schedules,
                trade confirms and ISDA Master Agreement, each between HSBC Bank
                USA,
                National Association and Supplemental Interest Trust, Structured
                Asset
                Securities Corporation Mortgage Pass-Through Certificates, Series
                2006-S1.</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="4%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="7%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">99.4
                </font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" colspan="2" valign="top" width="61%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Interest
                Rate Cap Agreement, dated as of February 28, 2006 (including schedules,
                trade confirms and ISDA Master Agreement (by reference)), each between
                HSBC Bank USA, National Association and Supplemental Interest Trust,
                Structured Asset Securities Corporation Mortgage Pass-Through
                Certificates, Series 2006-S1.</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>

      </table>
    </div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: -36pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div id="PGBRK" style="MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; MARGIN-RIGHT: 0pt">
      <div id="FTR">
        <div id="GLFTR" style="WIDTH: 100%" align="left">
        </div>
      </div>
      <div id="PN" style="PAGE-BREAK-AFTER: always">
        <div style="WIDTH: 100%; TEXT-ALIGN: center">
        </div>
        <div style="WIDTH: 100%; TEXT-ALIGN: center">
          <hr style="COLOR: black" noshade size="2">
        </div>
      </div>
      <div id="HDR">
        <div id="GLHDR" style="WIDTH: 100%" align="right">
        </div>
      </div>
    </div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>SIGNATURES</strong></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 36pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Pursuant
      to the requirements of the Securities Exchange Act of 1934, as amended, the
      Registrant has duly caused this report to be signed on its behalf by the
      undersigned hereunto duly authorized.</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div>
      <table cellpadding="0" cellspacing="0" width="100%">

          <tr bgcolor="#ffffff">
            <td align="left" valign="top" width="34%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="4%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="34%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr bgcolor="#ffffff">
            <td align="left" valign="top" width="34%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" colspan="2" valign="top" width="37%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">STRUCTURED
                ASSET SECURITIES CORPORATION</font></div>
            </td>
          </tr>
          <tr bgcolor="#ffffff">
            <td align="left" valign="top" width="34%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="4%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="34%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr bgcolor="#ffffff">
            <td align="left" valign="top" width="34%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="4%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">By:&#160;&#160;</font></div>
            </td>
            <td align="left" valign="top" width="34%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">/s/&#160;
                Ellen V. Kiernan</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY: Times New Roman">&#160;</font></div>
            </td>
          </tr>
          <tr bgcolor="#ffffff">
            <td align="left" colspan="2" valign="top" width="38%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="34%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">
                <hr style="COLOR: black" align="left" noshade size="1" width="100%">
              </div>
            </td>
          </tr>
          <tr bgcolor="#ffffff">
            <td align="left" colspan="2" valign="top" width="38%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="34%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Name:&#160;
                Ellen V. Kiernan</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Title:&#160;&#160;
                Senior Vice President</font></div>
            </td>
          </tr>

      </table>
    </div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Dated:
      </font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">February
      28, 2006</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div id="PGBRK" style="MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; MARGIN-RIGHT: 0pt">
      <div id="FTR">
        <div id="GLFTR" style="WIDTH: 100%" align="left">
        </div>
      </div>
      <div id="PN" style="PAGE-BREAK-AFTER: always">
        <div style="WIDTH: 100%; TEXT-ALIGN: center">
        </div>
        <div style="WIDTH: 100%; TEXT-ALIGN: center">
          <hr style="COLOR: black" noshade size="2">
        </div>
      </div>
      <div id="HDR">
        <div id="GLHDR" style="WIDTH: 100%" align="right">
        </div>
      </div>
    </div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><u>EXHIBIT
      INDEX</u></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div align="left">
      <table border="0" cellpadding="0" cellspacing="0" width="100%">

          <tr>
            <td valign="top" width="14%" style="border-bottom: medium none;">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><u>Exhibit
                No.</u></font></div>
            </td>
            <td valign="top" width="86%" style="border-bottom: medium none;">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><u>Description</u></font></div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="14%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="86%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="14%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">4.1</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="86%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Trust
                Agreement dated as of February 1, 2006, among Structured Asset Securities
                Corporation, as Depositor, Aurora Loan Services LLC, as Master Servicer,
                Clayton Fixed Income Services, Inc. as Credit Risk Manager, and U.S.
                Bank
                National Association, as Trustee.</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="14%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">99.1</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="86%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Mortgage
                Loan Sale and Assignment Agreement dated as of February 1, 2006,
                between
                Lehman Brothers Holdings Inc., as Seller, and Structured Asset Securities
                Corporation, as Purchaser.</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="14%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">99.2</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="86%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Servicing
                Agreement dated as of February 1, 2006, by and among Lehman Brothers
                Holdings Inc., as Seller, and Aurora Loan Services LLC, in the dual
                capacities of Servicer and Master Servicer.</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="14%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">99.3</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="86%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Interest
                Rate Swap Agreement, dated as of February 28, 2006 (including schedules,
                trade confirms and ISDA Master Agreement, each between HSBC Bank
                USA,
                National Association and Supplemental Interest Trust, Structured
                Asset
                Securities Corporation Mortgage Pass-Through Certificates, Series
                2006-S1.</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="14%" style="border-bottom: medium none;">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">99.4</font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td align="left" valign="top" width="86%" style="border-bottom: medium none;">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Interest
                Rate Cap Agreement, dated as of February 28, 2006 (including schedules,
                trade confirms and ISDA Master Agreement (by reference)), each between
                HSBC Bank USA, National Association and Supplemental Interest Trust,
                Structured Asset Securities Corporation Mortgage Pass-Through
                Certificates, Series 2006-S1. </font></div>
            </td>
          </tr>

      </table>
    </div>
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    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center">&#160;</div>
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{"company-data": {"conformed-name": "Structured Asset Securities Corp 2006-S1", "cik": "0001354503", "assigned-sic": "6189", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "333-127589-38", "film-number": "06688754"}, "business-address": {"street1": "745 7TH AVENUE", "city": "NEW YORK", "state": "NY", "zip": "10019", "phone": "2125267000"}, "mail-address": {"street1": "745 7TH AVENUE", "city": "NEW YORK", "state": "NY", "zip": "10019"}}
UNITED
      STATES
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)
February
      28, 2006
STRUCTURED
      ASSET SECURITIES CORPORATION (as Depositor under the Trust Agreement dated
      as of
      February 1, 2006, providing for the issuance of Structured Asset Securities
      Corporation Mortgage Pass-Through Certificates, Series 2006-S1)
Structured
      Asset Securities Corporation Mortgage Loan Trust
      2006-S1
(Exact
      Name of Issuing Entity as Specified in its Charter)
Structured
      Asset Securities
      Corporation
(Exact
      Name of Depositor as Specified in its Charter)
Lehman
      Brothers Holdings
      Inc.
(Exact
      Name of Sponsor as Specified in its Charter)
Structured
      Asset Securities
      Corporation
(Exact
      Name of Registrant as Specified in its Charter)
Delaware
333-127589
74-2440850
(State
                or Other Jurisdiction
Of
                Incorporation)
(Commission
File
                Number)
(I.R.S.
                Employer
Identification
                No.)
745
                Seventh Avenue, 7
th
Floor
New
                York, NY
10019
(Address
                of Principal Executive Offices)
(Zip
                Code)
Registrant's
      telephone number, including area code: (212) 526-7000
No
      Change
(Former
      Name or Former Address, if Changed Since Last Report)
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:
o
Written
      communications pursuant to Rule 425 under the Securities Act (17 CFR
      230.425)
o
Soliciting
      material pursuant to Rule 14a-12 under the Exchange Act (17 CFR
      240.14a-12)
o
Pre-commencement
      communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR
      240.14d-2(b))
o
Pre-commencement
      communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR
      240.13e-4(c))
Item
      8.01.
Other
      Events
The
      Registrant registered the issuance of Structured Asset Securities Corporation
      Mortgage Pass-Through Certificates, Series 2006-S1 on a delayed or continuous
      basis pursuant to Rule 415 under the Securities Act of 1933, as amended (the
      "Act"), by a Registration Statement on Form S-3 (Registration File No.
      333-127589-38) (the "Registration Statement"). Pursuant to the Registration
      Statement, the Registrant issued $432,534,000 aggregate principal amount of
      Class A1, Class A2, Class M1, Class M2, Class M3, Class M4, Class M5, Class
      M6,
      Class M7 and Class M8 Certificates of its Structured Asset Securities
      Corporation Mortgage Pass-Through Certificates, Series 2006-S1 on February
      28,
      2006. This Current Report on Form 8-K is being filed to satisfy an undertaking,
      contained in the definitive Prospectus dated September 26, 2005, as supplemented
      by the Prospectus Supplement dated February 23, 2006 (the "Prospectus
      Supplement"), to file a copy of the Trust Agreement (as defined below) and other
      material operative agreements executed in connection with the issuance of the
      Certificates, a form of which was filed as an exhibit to the Registration
      Statement.
The
      Certificates were issued pursuant to a Trust Agreement (the "Trust Agreement"),
      attached hereto as
Exhibit
      4.1
,
      dated
      as of February 1, 2006, among Structured Asset Securities Corporation, as
      depositor, Aurora Loan Services LLC, as Master Servicer, and U.S. Bank National
      Association, as Trustee. The "Certificates" consist of the following classes:
      Class A1, Class A2, Class M1, Class M2, Class M3, Class M4, Class M5, Class
      M6,
      Class M7, Class M8, , Class B1, Class B2, Class P, Class X, Class R and Class
      LT-R. The Certificates evidence all of the beneficial ownership interest in
      a
      trust fund (the "Trust Fund") that consists primarily of a pool of certain
      conventional, second lien, fixed rate, fully amortizing and balloon, residential
      mortgage loans, with an aggregate outstanding principal balance of $441,642,561
      as of February 1, 2006, together with certain other assets. Capitalized terms
      used herein and not otherwise defined shall have the meanings assigned to them
      in the Trust Agreement.
Item
                9.01. Financial Statements and Exhibits
(a)
Not
                applicable.
(b)
Not
                applicable.
(c)
Not
                applicable.
(d)
Exhibits:
4.1
Trust
                Agreement dated as of February 1, 2006, among Structured Asset Securities
                Corporation, as Depositor, Aurora Loan Services LLC, as Master Servicer,
                Clayton Fixed Income Services, Inc. as Credit Risk Manager, and U.S.
                Bank
                National Association, as Trustee.
99.1
Mortgage
                Loan Sale and Assignment Agreement dated as of February 1, 2006,
                between
                Lehman Brothers Holdings Inc., as Seller, and Structured Asset Securities
                Corporation, as Purchaser.
99.2
Servicing
                Agreement dated as of February 1, 2006, by and among Lehman Brothers
                Holdings Inc., as Seller, and Aurora Loan Services LLC, in the dual
                capacities of Servicer and Master Servicer.
99.3
Interest
                Rate Swap Agreement, dated as of February 28, 2006 (including schedules,
                trade confirms and ISDA Master Agreement, each between HSBC Bank
                USA,
                National Association and Supplemental Interest Trust, Structured
                Asset
                Securities Corporation Mortgage Pass-Through Certificates, Series
                2006-S1.
99.4
Interest
                Rate Cap Agreement, dated as of February 28, 2006 (including schedules,
                trade confirms and ISDA Master Agreement (by reference)), each between
                HSBC Bank USA, National Association and Supplemental Interest Trust,
                Structured Asset Securities Corporation Mortgage Pass-Through
                Certificates, Series 2006-S1.
SIGNATURES
Pursuant
      to the requirements of the Securities Exchange Act of 1934, as amended, the
      Registrant has duly caused this report to be signed on its behalf by the
      undersigned hereunto duly authorized.
STRUCTURED
                ASSET SECURITIES CORPORATION
By:
/s/ 
                Ellen V. Kiernan
Name: 
                Ellen V. Kiernan
Title:  
                Senior Vice President
Dated:
February
      28, 2006
EXHIBIT
      INDEX
Exhibit
                No.
Description
4.1
Trust
                Agreement dated as of February 1, 2006, among Structured Asset Securities
                Corporation, as Depositor, Aurora Loan Services LLC, as Master Servicer,
                Clayton Fixed Income Services, Inc. as Credit Risk Manager, and U.S.
                Bank
                National Association, as Trustee.
99.1
Mortgage
                Loan Sale and Assignment Agreement dated as of February 1, 2006,
                between
                Lehman Brothers Holdings Inc., as Seller, and Structured Asset Securities
                Corporation, as Purchaser.
99.2
Servicing
                Agreement dated as of February 1, 2006, by and among Lehman Brothers
                Holdings Inc., as Seller, and Aurora Loan Services LLC, in the dual
                capacities of Servicer and Master Servicer.
99.3
Interest
                Rate Swap Agreement, dated as of February 28, 2006 (including schedules,
                trade confirms and ISDA Master Agreement, each between HSBC Bank
                USA,
                National Association and Supplemental Interest Trust, Structured
                Asset
                Securities Corporation Mortgage Pass-Through Certificates, Series
                2006-S1.
99.4
Interest
                Rate Cap Agreement, dated as of February 28, 2006 (including schedules,
                trade confirms and ISDA Master Agreement (by reference)), each between
                HSBC Bank USA, National Association and Supplemental Interest Trust,
                Structured Asset Securities Corporation Mortgage Pass-Through
                Certificates, Series 2006-S1.