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) ~~January~~July 18, 2005

MS Structured Asset Corp. (Issuer in Respect of Saturns Trust No. 2003-12)
(Exact name of registrant as specified in its charter)

Delaware
(State or other jurisdiction
of incorporation)

001-16443
(Commission
File Number)

13-4026700
(IRS Employer
Identification No.)

1585 Broadway, New York, New York
(Address of principal executive offices)

10036
(Zip Code)

Registrant's telephone number, including area code 212-761-2520

(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 (see General Instruction A.2. below):

[ ] 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))

Section 8 - Other Events

Item 8.01. Other Events.

This current report on Form 8-K relates to the semi annual distribution reported to the holders of SATURNS Trust No. 2003-12, which was made on ~~January~~July 18, 2005.

Section 9 - Financial Statements and Exhibits

Item 9.01 Financial Statements and Exhibits.

99.1 Semi-Annual distribution report pursuant to the Trust Agreement for the distribution on ~~January~~July 18, 2005.

(Exhibit No. Description)

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.

LASALLE BANK NATIONAL ASSOCIATION, IN ITS CAPACITY AS TRUSTEE UNDER THE TRUST AGREEMENT ON BEHALF OF MS STRUCTURED ASSET CORP., REGISTRANT

By: /s/ Russell Goldenberg Russell Goldenberg Group Senior Vice President Date: ~~January~~July 21, 2005

Structured Asset Trust Unit Repackagings (SATURNS) DaimlerChrysler North America Holding Corp. Debenture Backed Series 2003-12 ABN AMRO Acct: 720552.1 Reporting Package Table of Contents Payment Date:Prior Payment:Next Payment:Record Date: 18-~~Jan~~Jul-0518-~~Jan~~Jul-05 1918-~~Jul~~Jan-~~0418~~0518-~~Jul~~Jan-0506 1213-~~Jan~~Jul-05 Administrator:Andy Streepey 312.904.9387andy.streepey@abnamro.com Analyst:~~Steve~~Jeff ~~Fernandez~~Brown 714.259.~~6204~~6233 ~~Steve~~jeffrey.~~Fernandez~~r.brown@abnamro.com Statement Date: 135 S. LaSalle Street, Suite 1625Chicago, IL 60603USA Statements to CertificateholdersCash Reconciliation SummaryBond Interest ReconciliationOther Related Information Other Related Information Rating InformationRealized Loss Detail Page 2Page 3Page 4Page 5 Page 6 Page 7Page 8 Page(s) Information is available for this issue from the following sources Issue Id: Monthly Data FileName: SAT00312 ~~SAT00312_200501_3~~SAT00312_200507_3.ZIP Closing Date: First Payment Date: Rated Final Payment: Date: 20-Aug-0320-Jan-04 18-Jan-31 Parties to The Transaction Depositor: MS Structured Asset Corp Underwriter: Morgan Stanley & Co. Incorporated Rating Agency: Moody's Investors Service, Inc./Standard & Poor's 800.246.5761 LaSalle Factor Line LaSalle Web Site www.etrustee.net Page 1 of 8 1214-~~Jan~~Jul-2005 - 1209:5251 (P542-P544) (c) 2005 LaSalle Bank N.A. Class CUSIP Original Opening Principal Principal Negative Closing Interest Interest Pass-Through Per $ 1000 Per $ 1000 Per $ 1000 Per $ 1000 Per $ 1000 Per $ 1000 Per $ 1000 Next Rate(3) WAC:WAMM: Payment Date:Prior Payment:Next Payment:Record Date: 50.736000% 18-~~Jan~~Jul-0518-~~Jan~~Jul-05 1918-~~Jul~~Jan-~~0418~~0518-~~Jul~~Jan-0506 1213-~~Jan~~Jul-05 Structured Asset Trust Unit Repackagings (SATURNS) DaimlerChrysler North America Holding Corp. Debenture Backed Series 2003-12 Face Value (1) Balance Payment Adj. or Loss Amortization Balance Payment (2) Adjustment Rate ~~624~~612 Grantor Trust Statement Date: ABN AMRO Acct: 720552.1 1000.000000000 0.000000000 0.000000000 1000.000000000 35.000000000 Fixed 0.00 0.00 0.000000000 7.~~00000000~~0000000000% 0.000000000 804110203 A UNIT 25,000,000.00 ~~25,000,000.00~~ 0.00 0.00 25,000,000.00 875,000.00 25,000,000.00 1000.000000000 0.000000000 0.000000000 1000.000000000 7.280000000 Fixed 0.00 0.00 0.000000000 1.~~45600000~~4560000000% 0.000000000 N 804110AA2 B UNIT 25,000,000.00 ~~25,000,000.00~~ 0.00 0.00 25,000,000.00 182,000.00 25,000,000.00 Total P&I Payment 0.00 0.00 25,000,000.00 25,000,000.00 1,057,000.00 Total 25,000,000.00 0.00 0.00 1,057,000.00 1214-~~Jan~~Jul-2005 - 1209:5251 (P542-P544) (c) 2005 LaSalle Bank N.A. Page 2 of 8 Notes: (1) N denotes notional balance not included in total (2) Accrued Interest Plus/Minus Interest Adjustment Minus Deferred Interest equals Interest Payment (3) Estimated. * Denotes Controlling Class Structured Asset Trust Unit Repackagings (SATURNS) Payment Date:Prior Payment:Next Payment:Record Date: 18-~~Jan~~Jul-0518-~~Jan~~Jul-05 1918-~~Jul~~Jan-~~0418~~0518-~~Jul~~Jan-0506 1213-~~Jan~~Jul-05 DaimlerChrysler North America Holding Corp. Debenture Backed Series 2003-12 ABN AMRO Acct: 720552.1 Statement Date: Cash Reconciliation Summary Current Scheduled Interest Interest Summary Less Deferred Interest Plus Gross Advance Interest Less PPIS Reducing Scheduled Int 1,057,000.00 0.000.00 Less ASER Interest Adv Reduction 0.00 Less Other Adjustment 0.00 Total 1,057,000.00 Unscheduled Interest:Prepayment Penalties 0.00 Yield Maintenance Penalties 0.00 Other Interest Proceeds 0.00 Total 0.00 Less Fees & Expenses Paid By/To Servicer Less Fee Paid To Servicer Less Fee Strips Paid by Servicer Special Servicing Fees Interest Due Serv on Advances Recoup of Prior Advances Misc. Fees & Expenses Total Unscheduled Fees & ExpensesTotal Interest Due Trust Less Fees & Expenses Paid By/To TrustTrustee FeeFee StripsMisc. FeesInterest Reserve Withholding Plus Interest Reserve DepositTotal Total Interest Due Certs Principal Summary Scheduled Principal:Current Scheduled PrincipalAdvanced Scheduled PrincipalScheduled PrincipalUnscheduled Principal:CurtailmentsPrepayments in FullLiquidation ProceedsRepurchase ProceedsOther Principal ProceedsTotal Unscheduled Principal Remittance Principal Remittance P&I Due Trust Remittance P&I Due Certs Pool Balance Summary Beginning PoolScheduled PrincipalUnscheduled PrincipalDeferred InterestLiquidationsRepurchases Ending Pool Balance Count Principal Interest Prior OutstandingPlus Current PeriodLess Recovered Ending Outstanding Servicing Fee Summary Current Servicing FeesPlus Fees Advanced for PPISLess Reduction for PPISPlus Delinquent Servicing Fees Total Servicing Fees PPIS Summary Gross PPISReduced by PPIEReduced by Shortfalls in FeesReduced by Other Amounts PPIS Reducing ScheduledInterest PPIS Reducing Servicing FeePPIS Due Certificate 0.00 0.00 0.000.00 0.00 0.00 1,057,000.00 0.000.000.000.00 0.00 0.000.000.00 0.000.000.000.000.000.000.00 1,057,000.00 1,057,000.00 25,000,000.00 2 0.000.00 0 0.000.00 0 0.00 0 25,000,000.00 2 0.00 0.00 0.00 0.00 0.00 0.00 0.000.000.000.00 0.00 0.000.000.000.000.000.00 0.00 0.00 1,057,000.00 Interest Not Advanced ( Current Period ) 0.00 0.00 Workout FeesLiquidation Fees 0.000.00 Less Non Recovered 0.00 0.000.00 0.00 0.00 Advance Summary (Advance Made by Servicer) 0 Page 3 of 8 1214-~~Jan~~Jul-2005 - 1209:5251 (P542-P544) (c) 2005 LaSalle Bank N.A. Structured Asset Trust Unit Repackagings (SATURNS) Class Accrued Payment Date:Prior Payment:Next Payment:Record Date: 18-~~Jan~~Jul-0518-~~Jan~~Jul-05 1918-~~Jul~~Jan-~~0418~~0518-~~Jul~~Jan-0506 1213-~~Jan~~Jul-05 DaimlerChrysler North America Holding Corp. Debenture Backed Series 2003-12 ABN AMRO Acct: 720552.1 Bond Interest Reconciliation Deductions Allocable Deferred & Prior Prepay- Other Additions Interest Credit Support Original Current(4) Accrual Int. Short- falls Due ment Interest ~~Interest~~Int erest (2) Payment Amount PPIS ~~Interest~~Int erest Certificate Accretion Interest Loss/Exp Interest Penalties Proceeds (1) Interest Shortfalls Certificate Rate Pass Thru Method Days Outstanding Remaining Statement Date: Distributable Current Period (Shortfall)/ Recovery Int Accrual on Prior Shortfall (3) 1.001.00 0.00 0.00 0.00 0.00 0.00 A UNIT 180 875,000.00 875,000.00 875,000.00 0.00 NA NA 30/360 7.000000000% 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 B UNIT 180 182,000.00 182,000.00 182,000.00 0.00 NA NA 30/360 1.456000000% 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1,057,000.00 1,057,000.00 1,057,000.00 0.00 0.00 0.00 0.00 (2) Accrued - Deductions + Additions Interest (3) Includes interest accrued on outstanding Interest Shortfalls and/or Loss Allocations. Where applicable. 1214-~~Jan~~Jul-2005 - 1209:5251 (P542-P544) (c) 2005 LaSalle Bank N.A. Page 4 of 8 (1) Other Interest Proceeds are additional interest amounts specifically allocated to the bond(s) and used in determining the bonds Distributable Interest. (4) Determined as follows: (A) the ending balance of all the classes less (B) the sum of (i) the ending balance of the class and (ii) the ending balance of all classes which are not subordinate to the class divided by (A). Structured Asset Trust Unit Repackagings (SATURNS) Payment Date:Prior Payment:Next Payment:Record Date: 18-~~Jan~~Jul-0518-~~Jan~~Jul-05 1918-~~Jul~~Jan-~~0418~~0518-~~Jul~~Jan-0506 1213-~~Jan~~Jul-05 DaimlerChrysler North America Holding Corp. Debenture Backed Series 2003-12 ABN AMRO Acct: 720552.1 Other Related Information Statement Date: Swap Receipents Swap Amount Received Next Swap Rate None 0.00 0.00% Swap Information Page 5 of 8 1214-~~Jan~~Jul-2005 - 1209:5251 (P542-P544) (c) 2005 LaSalle Bank N.A. Structured Asset Trust Unit Repackagings (SATURNS) Payment Date:Prior Payment:Next Payment:Record Date: 18-~~Jan~~Jul-0518-~~Jan~~Jul-05 1918-~~Jul~~Jan-~~0418~~0518-~~Jul~~Jan-0506 1213-~~Jan~~Jul-05 DaimlerChrysler North America Holding Corp. Debenture Backed Series 2003-12 ABN AMRO Acct: 720552.1 Other Related Information Statement Date: The underlying security issuer or guarantor, as applicable, is subject to the informational requirements ~~ofthe~~of the Exchange Act. ~~The~~Theunderlying ~~underlying~~ security issuer or guarantor, as applicable, currently files reports, proxy statements and other information with the SEC. Those periodic reports, current reports and ~~otherreports~~other reports and other information can be inspected and copied at the public ~~reference~~referencefacilities ~~facilities~~ maintained ~~bythe~~by the SEC at Room 1024, 450 Fifth Street, N.W., Washington, D.C. 20549, at prescribed rates. The ~~SECalso~~SEC ~~maintains~~alsomaintains a website on the internet at http://www.sec.gov at which users can view and ~~downloadcopies~~download copies of reports, proxy, ~~information~~informationstatements ~~statements~~ and other information filed electronically. In addition, those reports and other information may also be obtained from ~~the~~theunderlying ~~underlying~~ security issuer by ~~makinga~~making a request to the underlying security issuer. Page 6 of 8 1214-~~Jan~~Jul-2005 - 1209:5251 (P542-P544) (c) 2005 LaSalle Bank N.A. Structured Asset Trust Unit Repackagings (SATURNS) Payment Date:Prior Payment:Next Payment:Record Date: 18-~~Jan~~Jul-0518-~~Jan~~Jul-05 1918-~~Jul~~Jan-~~0418~~0518-~~Jul~~Jan-0506 1213-~~Jan~~Jul-05 DaimlerChrysler North America Holding Corp. Debenture Backed Series 2003-12 ABN AMRO Acct: 720552.1 Rating Information Class CUSIP Fitch Moody's S&P Fitch Moody's S&P Original Ratings Rating Change/Change Date(1) Statement Date: A UNIT 804110203 NR A3 BBB+ BBB 10/30/03 B UNIT 804110AA2 NR A3 BBB+ BBB 10/30/03 Page 7 of 8 1214-~~Jan~~Jul-2005 - 1209:5251 (P542-P544) (c) 2005 LaSalle Bank N.A. NR - Designates that the class was not rated by the rating agency. (1) Changed ratings provided on this report are based on information provided by the applicable rating agency via electronic transmission. It shall be understood that this transmission will generally have been provided to LaSalle within 30 days of the payment date listed on this statement. Because ratings may ~~havechanged~~have changed during the 30 day window, or may not be being provided by the rating agency in an electronic format and therefore ~~not~~notbeing ~~being~~ updated ~~onthis~~on this report, LaSalle recommends that investors obtain current rating information directly from the rating agency. Structured Asset Trust Unit Repackagings (SATURNS) Payment Date:Prior Payment:Next Payment:Record Date: 18-~~Jan~~Jul-0518-~~Jan~~Jul-05 1918-~~Jul~~Jan-~~0418~~0518-~~Jul~~Jan-0506 1213-~~Jan~~Jul-05 DaimlerChrysler North America Holding Corp. Debenture Backed Series 2003-12 ABN AMRO Acct: 720552.1 Realized Loss Detail Period Disclosure Control # Appraisal Date Appraisal Value ~~BeginningScheduled~~Beginning Scheduled Balance Gross Proceeds Gross Proceeds as a % of Sched. Balance Aggregate Liquidation Expenses * Net Liquidation Proceeds Net Proceeds as a % of Sched. Balance Realized Loss Statement Date: Current ~~TotalCumulative~~Total 12Cumulative 14-~~Jan~~Jul-2005 - 1209:5251 (P542-P544) (c) 2005 LaSalle Bank N.A. Page 8 of 8 * Aggregate liquidation expenses also include outstanding P&I advances and unpaid servicing fees, unpaid trustee fees, etc..

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