SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 UNITED STATES ASSET-BACKED ISSUER THE SECURITIES EXCHANGE ACT OF 1934 For the monthly distribution period from (Exact name of depositor as specified in its charter) (State or other jurisdiction of incorporation or organization of the issuing entity) (Telephone number, including area code) 01-~~Sep~~Dec-07 Structured Asset Securities Corporation (I.R.S. Employer Identification No.) Not Applicable (Address of principal executive offices of issuing entity) (Zip Code) DISTRIBUTION REPORT PURSUANT TO SECTION 13 OR 15(d) OF to 02-~~Aug~~Nov-07 (Exact name of issuing entity as specified in its charter) Commission File Number of Issuing entity: 333-139693-01 Commission File Number of depositor: 333-139693 (Exact name of sponsor as specified in its charter) Lehman Brothers Holdings Inc. (Former name, former address, if changed since last report) No Change Lehman Mortgage Trust 2007-7 7 4 5 S e v e n t h A v e n u e New York, New York 10019 (212) 526-7000 New York FORM 10-D

Registered/reporting pursuant to (check one)

Section 15(d)

Name of exchange

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