EXHIBIT 4.1



                            FORM OF REGISTERED UNIT


                         CBT SERIES 2003-1 UNITS TRUST
                          CORPORATE BOND TRACERS UNITS


THIS CERTIFICATE IS A GLOBAL SECURITY WITHIN THE MEANING OF THE TRUST AGREEMENT
HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A
NOMINEE OF A DEPOSITARY. THIS UNIT IS EXCHANGEABLE FOR UNITS REGISTERED IN THE
NAME OF A PERSON OTHER THAN THE DEPOSITARY OR ITS NOMINEE ONLY IN THE LIMITED
CIRCUMSTANCES DESCRIBED IN THE TRUST AGREEMENT AND MAY NOT BE TRANSFERRED
EXCEPT AS A WHOLE BY THE DEPOSITARY TO A NOMINEE OF THE DEPOSITARY OR BY A
NOMINEE OF THE DEPOSITARY TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE
DEPOSITARY.

UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE TRUSTEE OR ITS
AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY CERTIFICATE
ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO
CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

THIS UNIT MAY BE SUBJECT TO ADDITIONAL RESTRICTIONS ON TRANSFER AS PROVIDED IN
THE TRUST AGREEMENT FOR THE TRUST TO WHICH THIS UNIT RELATES.

THIS UNIT SHALL BE CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW
YORK, APPLICABLE TO AGREEMENTS MADE AND TO BE PERFORMED THEREIN AND THE
OBLIGATIONS, RIGHTS AND REMEDIES OF THE PARTIES HEREUNDER SHALL BE DETERMINED
IN ACCORDANCE WITH SUCH LAWS.


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Unit No. 1                                                   CUSIP No.

AGGREGATE INITIAL AMOUNT OF UNITS: $25,000,000

AGGREGATE INITIAL NUMBER
OF ALL UNITS:  25,000 ($1,000 Unit
Principal Balance Each)



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                         CBT SERIES 2003-1 UNITS TRUST
                          CORPORATE BOND TRACERS UNITS

     This certifies that Cede & Co. is the registered owner of an undivided
fractional interest in the Trust Property referred to below. The amount due on
the Units represented by this Certificate on any Distribution Date is the
fractional undivided interest represented by such Units of the amount of the
distribution on the Units as determined pursuant to the Trust Agreement.

     The Trust Property will be held in trust by the Trustee identified in the
Trust Agreement (the "Trust"). The Trust has been created pursuant to a Trust
Agreement, dated as of September 25, 2003, between LaSalle Bank National
Association, as Trustee of the Trust (the "Trustee") and MS Structured Asset
Corp. (the "Depositor"), which incorporates the Standard Terms for Trust
Agreements (the "Standard Terms"), dated as of September 25, 2003, between the
Trustee and the Depositor (including such Standard Terms, the "Trust
Agreement").

     To the extent not defined herein, all capitalized terms shall have the
meanings assigned to such terms in the Trust Agreement (and the Schedules
attached thereto). The Units represented by this Certificate are the Units
described in the Trust Agreement and are issued under and subject to the terms,
provisions and conditions of the Trust Agreement. By acceptance of the Units
represented by this Certificate, the Holder assents to and becomes bound by the
Trust Agreement.

     The Trust Property consists of the Underlying Securities and all payments
on or collections in respect of such Underlying Securities (excluding the
Retained Interest of the Depositor and any amounts that constitute
Reimbursement Payments under the Trust Agreement); all the Trustee's right,
title and interest under any Swap Agreement and any related Guarantee; all
Permitted Investments and all funds from time to time deposited in certain
segregated accounts held by the Trustee in trust and for the benefit of the
Unitholders representing interests in such Trust; any other asset described in
the Trust Agreement as constituting a portion of such Trust Property; provided
that the Trust Property shall not include any amounts (and income thereon)
invested by the Trustee in a Permitted Investment on behalf of the Depositor.

     Subject to the terms and conditions of the Trust Agreement (including the
availability of funds for distributions and any grace period or cure period
applicable to the Trust Property) and to the prior obligation of the Trust to
pay (i) all amounts due to the Swap Counterparty pursuant to the Swap Agreement
and (ii) all unpaid Extraordinary Trust Expenses, and until the obligations
created by the Trust Agreement shall have terminated in accordance therewith,
there will be distributed on each Distribution Date, to the Person in whose
name this Certificate

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is registered at the close of business on the Record Date, such Unitholder's
fractional undivided interest in the amounts to be distributed to Holders of
Units pursuant to the Trust Agreement on such Distribution Date. The amount to
be distributed on the Scheduled Final Distribution Date will include the
repayment of principal and interest, in each case, as specified in Schedule IV
thereto (as amended from time to time).

     Distributions on this Certificate will be made by wire transfer in
accordance with a written notice to the Trustee providing appropriate wire
transfer instructions given no later than 15 calendar days prior to the
applicable Distribution Date. If no such notice has been given, distributions
will be made by the Trustee by check mailed to the Unitholder of record at its
address as it appears in the Unit Register without the presentation or
surrender of this Certificate or the making of any notation hereon. Except as
otherwise provided in the Trust Agreement and notwithstanding the above, the
final distribution on this Certificate will be made after due notice by the
Trustee of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency maintained for that
purpose by the Trustee in Chicago, Illinois.

     This Certificate does not purport to summarize the Trust Agreement and
reference is hereby made to the Trust Agreement for information with respect to
the rights, benefits, obligations and duties evidenced thereby. A copy of the
Trust Agreement may be examined during normal business hours at the Corporate
Trust Office of the Trustee, located at 135 South LaSalle Street, Suite 1625,
Chicago, Illinois 60603 and at such other places, if any, designated by the
Trustee, by any Unitholder upon request.

     Reference is hereby made to the further terms of this Certificate set
forth on the reverse hereof, which further terms shall for all purposes have
the same effect as if set forth at this place.

     Unless the certificate of authentication hereon shall have been executed
by an authorized officer of the Trustee, by manual signature, this Certificate
shall not entitle the Holder hereof to any benefit under the Trust Agreement or
be valid for any purpose.






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     IN WITNESS WHEREOF, the Trustee, on behalf of the Trust, has caused this
Certificate to be duly executed.

                                                 CBT SERIES 2003-1 UNITS TRUST

                                                 By: LASALLE BANK NATIONAL
                                                 ASSOCIATION, as Trustee

                                                 By:
                                                     ---------------------------
                                                     Authorized Signatory

DATED:

[SEAL]

Trustee's Certificate of
Authentication:


                       This is one of the Units referred
                     to in the within-mentioned Agreement.


                                                 LASALLE BANK NATIONAL
                                                 ASSOCIATION, as
                                                 Authenticating Agent

                                                 By:
                                                     ---------------------------
                                                     Authorized Signatory







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                         CBT SERIES 2003-1 UNITS TRUST
                          CORPORATE BOND TRACERS UNITS


     The Trust Agreement permits the amendment thereof, in certain
circumstances, without the consent of the Holders of any of the Certificates.

     As provided in the Trust Agreement and subject to certain limitations
therein set forth, the transfer of this Certificate is registerable in the Unit
Register upon surrender of this Certificate for registration of transfer at the
office or agency maintained by the Trustee in Chicago, Illinois, accompanied by
a written instrument of transfer and, if applicable, a transfer letter in form
and substance satisfactory to the Trustee duly completed and executed by the
Holder hereof or such Holder's attorney duly authorized in writing, and
thereupon one or more new Certificates of authorized denominations evidencing
the same aggregate interest in the Trust will be issued to the designated
transferee.

     As provided in the Trust Agreement and subject to certain limitations
therein set forth, Certificates are exchangeable for new Certificates
representing different numbers of Units which evidence the same aggregate
interest in the Trust, as requested by the Holder surrendering the same. No
service charge will be made for any such registration of transfer or exchange,
but the Trustee may require payment of a sum sufficient to cover any tax or
governmental charges payable in connection therewith.

     The Depositor, the Trustee and any agent of the Depositor or the Trustee
may treat the person in whose name this Certificate is registered as the owner
hereof for all purposes, and none of the Depositor, the Trustee, or any such
agent shall be affected by any notice to the contrary.

     The obligations and responsibilities created by the Trust Agreement and
the Trust created thereby will terminate upon the payment to Unitholders of all
amounts required to be paid to them pursuant to the Trust Agreement.

     Notwithstanding anything contained in the Trust Agreement to the contrary
the Trust Agreement has been accepted by LaSalle Bank National Association as
Trustee and in no event shall LaSalle Bank National Association have any
liability for the representations, warranties, covenants, agreements or other
obligations of the Depositor thereunder or in any of the certificates, notices
or agreements delivered pursuant thereto, as to all of which recourse shall be
had solely to the assets of the Depositor, and under no circumstances shall
LaSalle Bank National Association be personally liable for the payment of any
indebtedness or expenses of the Trust. The Units do not represent interests in
or obligations of the Trustee and the Trustee shall not be responsible or
accountable

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for any tax, accounting or other treatment proposed to be applied to the Units
or any interest therein except as expressly provided in the Trust Agreement.































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                                   ASSIGNMENT

     FOR VALUE RECEIVED the undersigned hereby sells, assigns and transfers
unto

PLEASE INSERT SOCIAL SECURITY
OR OTHER IDENTIFYING NUMBER
OF ASSIGNEE

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(Please print or typewrite name and address, including postal zip code, of
assignee)

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the within Certificate, and all rights thereunder, hereby irrevocably
constituting and appointing

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Attorney to transfer said Certificate on the books of the Unit Registrar, with
full power of substitution in the premises.


Dated: _______________________________________________________________________*/


Signature Guaranteed: ________________________________________________________*/


*/ NOTICE: The signature to this assignment must correspond with the name as it
appears upon the face of the within Certificate in every particular, without
alteration, enlargement or any change whatever. Such signature must be
guaranteed by a member of the New York Stock Exchange or a commercial bank or
trust company.





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