10-D 1 sac07wf1_10d-200709.txt UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington D.C. 20549 FORM 10-D ASSET-BACKED ISSUER DISTRIBUTION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the monthly distribution period from: August 02, 2007 to September 01, 2007 Commission File Number of issuing entity: 333-133985-56 Structured Asset Securities Corporation Mortgage Loan Trust 2007-WF1 (Exact name of issuing entity as specified in its charter) Commission File Number of depositor: 333-133985 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) New York (State or other jurisdiction of incorporation or organization of the issuing entity) Not Applicable (I.R.S. Employer Identification No.) 745 Seventh Avenue New York, NY 10019 (Address of principal executive offices of the issuing entity) (Zip Code) (212) 526-7000 (Telephone number, including area code) Not Applicable (Former name, former address, if changed since last report) Registered/reporting pursuant to (check one) Title of Section Section Section Name of Exchange Class 12(b) 12(g) 15(d) (If Section 12(b)) A1 _____ _____ __X___ ____________ A2 _____ _____ __X___ ____________ A3 _____ _____ __X___ ____________ A4 _____ _____ __X___ ____________ A5 _____ _____ __X___ ____________ A6 _____ _____ __X___ ____________ M1 _____ _____ __X___ ____________ M2 _____ _____ __X___ ____________ M3 _____ _____ __X___ ____________ M4 _____ _____ __X___ ____________ M5 _____ _____ __X___ ____________ M6 _____ _____ __X___ ____________ M7 _____ _____ __X___ ____________ M8 _____ _____ __X___ ____________ M9 _____ _____ __X___ ____________

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes __X__ No ____ Part I - DISTRIBUTION INFORMATION Item 1. Distribution and Pool Performance Information On September 25, 2007 a distribution was made to holders of Structured Asset Securities Corporation Mortgage Loan Trust 2007-WF1. The distribution report is attached as an Exhibit to this Form 10-D. Please see Item 9(b), Exhibit 99.1 for the related information. Part II - OTHER INFORMATION Item 9. Exhibits. (a) The following is a list of documents filed as part of this Report on Form 10-D: (99.1) Monthly report distributed to holders of Structured Asset Securities Corporation Mortgage Loan Trust 2007-WF1, relating to the September 25, 2007 distribution. (99.2) Clayton Credit Risk Management Report (b) The exhibits required to be filed by the Registrant pursuant to this Form are listed above and in the Exhibit Index that immediately follows the signature page hereof. 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 thereunto duly authorized. Structured Asset Securities Corporation Mortgage Loan Trust 2007-WF1 (Issuing Entity) Aurora Loan Services LLC (Master Servicer) /s/ Michele Olds Michele Olds, Vice President Servicer Oversight Date: October 02, 2007 EXHIBIT INDEX Exhibit Number Description EX-99.1 Monthly report distributed to holders of Structured Asset Securities Corporation Mortgage Loan Trust 2007-WF1, relating to the September 25, 2007 distribution. EX-99.2 Clayton Credit Risk Management Report EX-99.1 Structured Asset Securities Corporation Mortgage Pass-Through Certificates Distribution Date: 9/25/2007 Structured Asset Securities Corporation Mortgage Pass-Through Certificates Series 2007-WF1 Contact: Customer Service - CTSLink Wells Fargo Bank, N.A. Securities Administration Services 8480 Stagecoach Circle Frederick, MD 21701-4747 www.ctslink.com Telephone: 1-866-846-4526 Fax: 240-586-8675

REO Detail - All Mortgage Loans in REO during Current Period

Foreclosure Detail - All Mortgage Loans in Foreclosure during Current Period

Bankruptcy Detail - All Mortgage Loans in Bankruptcy during Current Period

Prepayment Rates

EX-99.2 (logo) CLAYTON SASCO 2007-WF1 Credit Risk Management Report August 2007 (C) 2007 Clayton Fixed Income Services Inc. All rights reserved (page) The information contained in this Report is based upon a specific point in time and reflects performance solely through that point in time. It does not forecast the performance of the portfolio in the future. The information in this Report is not investment advice concerning a particular portfolio or security, and no mention of a particular security in this Report constitutes a recommendation to buy, sell, or hold that or any security. The Report is based upon information provided to Clayton Fixed Income Services Inc. by third parties and therefore Clayton Fixed Income Services Inc. cannot, and does not, warrant that the information contained in this Report is accurate or complete. (page) Table of Contents Section One Exectuvie Summary Section Two Loan-Level Report Section Three Prepayment Penalty Analysis Section Four Mortgage Insurance Report Section Five Loss Analysis Section Six Analytics (page) Section One Exectuvie Summary (page) SASCO 2007-WF1 Executive Summary August 2007 Transaction Summary

Collateral Summary

(page)

Collateral Statistics

Prepayments

Prepayment Penalty Analysis For each remittance, Clayton reconciles the prepayment penalties that are collected by the servicers and remitted to the trust to ensure all appropriate funds are passed to the certificateholders. Please refer to the Prepayment Penalty Analysis section of this report for details regarding paid-off loans with prepayment penalty flags. The table below provides a summary of Clayton's reconciliation for this remittance.

Loss Analysis Loss Issues for Current Month For each remittance, Clayton analyzes each loan-level loss to ensure that the accurate amount of sale, MI, and hazard insurance proceeds are remitted to the trust. We also review these losses to ensure servicing advances, such as escrow advances and foreclosure fees, are reasonable. If any discrepancies are identified, Clayton actively pursues the servicer to mitigate the loss. Please refer to the Loss Analysis section of this report for details regarding losses to the security. Below is a summary of the losses passed through in this remittance. (page)

(page) Section Two Loan-Level Report (page) Loan-Level Report Definitions * FICO(R):: Represents the borrower's credit score at the time of securitization/origination. * Last Paid Date: Either the interest paid-through date or the last contractually due payment made by the borrower. Clayton Fixed Income Services Inc. uses this date to calculate delinquencies. * Valuation: Represents what is believed to be the most accurate known value of a property based on Clayton Fixed Income Services Inc.'s internal formulas. Several value appraisals may exist for a property, yet only what is believed to be the most accurate value according to these formulas is shown on the report. When no value is available, a valuation known as an "internal estimate" is calculated according to an internal formula that adjusts the original value of the property by the Housing Price Index (HPI) and a discount based on credit class. * Liquidation Date: Clayton Fixed Income Services Inc.'s internal estimate of the date on which the loan will liquidate if it proceeds through foreclosure and REO. This date takes into consideration servicing and state foreclosure timelines, as well as an estimated REO marketing period. * Estimated Loss/(Gain): Clayton Fixed Income Services Inc.'s internal estimate of the loss (or gain) that the loan will experience if it liquidates on the Liquidation Date. * Delinquency Status: Indicates the monthly payment and delinquency history for an individual loan. The right-most character specifies the last known delinquency status, according to the following: * C The contractually due payment arrived on time. * 3 The contractually due payment has not arrived within thirty days. * 6 The contractually due payment has not arrived within sixty days. * 9 The contractually due payment has not arrived within ninety days. * F The property is in the process of foreclosure. * R The property is real estate owned (REO). * 0 The mortgage has either liquidated or been paid off. * OTS Delinquency Method: A current loan becomes 30 days delinquent if the scheduled payment is not made by the close of business on the corresponding day of the following month. * MBA Delinquency Method: A current loan becomes 30 days delinquent if the scheduled payment is not made by the close of business on the last day of the month in which the payment was due. (page) SASCO 2007-WF1 Loan-Level Report Mortgage Data Through: July 31, 2007 Watchlist

(page) Section Three Prepayment Penalty Analysis (page) SASCO 2007-WF1 Prepayment Penalty Analysis Trustee Remittance Date: August 25, 2007

(page) SASCO 2007-WF1 Paid-Off Mortgages With Prepayment Flags Trustee Remittance Date: August 25, 2007

(page) Section Four Mortgage Insurance Report (page) SASCO 2007-WF1 Mortgage Insurance Claim Summary Mortgage Data Through: July 31, 2007 Claim Payment Breakdown

(page) Section Five Loss Analysis (page) SASCO 2007-WF1 Historical Monthly Losses Losses Through: July 31, 2007

(page) Section Six Analytics (page) SASCO 2007-WF1 FICO Distribution by Status Mortgage Data Through: July 31, 2007

(page) SASCO 2007-WF1 Loan-to-Value Distribution by Status Mortgage Data Through: July 31, 2007

(page) SASCO 2007-WF1 Balance Distribution by Status Mortgage Data Through: July 31, 2007

(page) SASCO 2007-WF1 Mortgage Type Distribution by Status Mortgage Data Through: 2007

(page) SASCO 2007-WF1 Mortgage Term Distribution by Status Mortgage Data Through: July 31, 2007

(page) SASCO 2007-WF1 Mortgage Purpose Distribution Mortgage Data Through: July 31, 2007

(page) SASCO 2007-WF1 Ownership Distribution by Status Mortgage Data Through: July 31, 2007

(page) SASCO 2007-WF1 Delinquent Balance Over Time Mortgage Data Through: July 31, 2007

(page) SASCO 2007-WF1 Delinquent Count Over Time Mortgage Data Through: July 31, 2007

(page) SASCO 2007-WF1 Conditional Prepayment Rates Mortgage Data Through: July31, 2007

(page) SASCO 2 007- WF1 Historical SDA Performance Mortgage Data Through: July 31, 2007

Structured Asset Securities CORP Mortgage Loan Trust 2007-WF1 10-D