EXHIBIT 4-xx


                                TRUST AGREEMENT
                                       OF
                        MORGAN STANLEY CAPITAL TRUST VI

         THIS TRUST AGREEMENT is made as of September 24, 2001 (this "Trust
Agreement"), among Morgan Stanley Dean Witter & Co., a Delaware corporation, as
depositor (the "Depositor"), The Bank of New York (Delaware), a Delaware
banking corporation, as Delaware Trustee (the "Delaware Trustee"), The Bank of
New York, a New York banking corporation, as property trustee (the "Property
Trustee" and, together with the Delaware Trustee, the "Issuer Trustees"), and
Alexander C. Frank and Debra M. Aaron, individuals, as administrators
(together, the "Administrators"). The Depositor, the Issuer Trustees and the
Administrators hereby agree as follows:

         1. The trust created hereby shall be known as Morgan Stanley Capital
Trust VI (the "Issuer Trust"), in which name the Issuer Trustees or the
Depositor, to the extent provided herein, may conduct the business of the
Issuer Trust, make and execute contracts, and sue and be sued.

         2. The Depositor hereby assigns, transfers, conveys and sets over to
the Issuer Trustee the sum of $10. It is the intention of the parties hereto
that the Issuer Trust created hereby constitute a business trust under Chapter
38 of Title 12 of the Delaware Code, 12 Del. C. ss. 3801, et seq. (the
"Business Trust Act"), and that this document constitute the governing
instrument of the Issuer Trust. The Issuer Trustees are hereby authorized and
directed to execute and file a certificate of trust with the Delaware Secretary
of State in accordance with the provisions of the Business Trust Act.

         3. An amended and restated Trust Agreement satisfactory to each party
to it and substantially in the form to be included as an exhibit to the 1933
Act Registration Statement (as herein defined), or in such other form as the
parties thereto may approve, will be entered into to provide for the
contemplated operation of the Issuer Trust created hereby and the issuance of
the Capital or Preferred Securities and Common Securities referred to therein.
Prior to the execution and delivery of such amended and restated Trust
Agreement, the Issuer Trustees shall not have any duty or obligation hereunder
or with respect of the trust estate, except as otherwise required by applicable
law or as may be necessary to obtain prior to such execution and delivery any
licenses, consents or approvals required by applicable law or otherwise.
Notwithstanding the foregoing, the Issuer Trustees may take all actions deemed
proper as are necessary to effect the transactions contemplated herein. It is
the intent of the parties hereto that the Administrators shall not be trustees
with respect to the Issuer Trust and this Trust Agreement shall be construed in
a manner consistent with such intent.

         4. The Depositor, as the depositor of the Issuer Trust, is hereby
authorized and appointed as the Issuer Trust's and the Issuer Trustees' true
and lawful attorney-in-fact and agent (i) to file with the Securities and
Exchange Commission (the "Commission") and to execute, in the case of the 1933
Act Registration Statement and 1934 Act Registration Statement (each as herein
defined) and any and all amendments thereto, including pre-effective and
post-effective amendments, on behalf of the Issuer Trust, (a) a Registration
Statement (the "1933 Act Registration Statement"), including pre-effective or
post-effective amendments thereto, with all exhibits thereto, and any other
documents that may be required in connection therewith, relating to the
registration under the Securities Act of






1933, as amended (the "1933 Act"), of the Capital or Preferred Securities of
the Issuer Trust, (b) any preliminary prospectus or prospectus or supplement
thereto relating to the Capital or Preferred Securities required to be filed
pursuant to the 1933 Act, and (c) a Registration Statement on Form 8-A or other
appropriate form (the "1934 Act Registration Statement"), including all
pre-effective and post-effective amendments thereto, with all exhibits thereto,
and with any other documents that may be required in connection therewith,
relating to the registration of the Capital or Preferred Securities of the
Issuer Trust under the Securities Exchange Act of 1934, as amended; (ii) to
file with the New York Stock Exchange, Inc., the American Stock Exchange LLC,
The London Stock Exchange plc, The Luxembourg Stock Exchange, The Paris Bourse
or other stock exchange or securities market, or the National Association of
Securities Dealers (the "NASD"), and execute and verify on behalf of the Issuer
Trust a listing application and all other applications, statements,
certificates, agreements and other instruments, under seal or otherwise, as
shall be necessary or desirable, and do or cause to be done all such acts and
things in the name of and on behalf of the Issuer Trust to meet the
requirements of any such stock exchange, securities market or the NASD's Nasdaq
National Market, or to appear before the appropriate representatives of
committees of any such stock exchange or securities market, in order to cause
the Capital or Preferred Securities to be listed on any such stock exchange or
securities market; (iii) to file, execute and verify on behalf of the Issuer
Trust such applications, reports, surety bonds, irrevocable consents,
appointments of attorney for service of process and other papers and documents
as shall be necessary or desirable to register or qualify the Capital or
Preferred Securities for offer and sale under the securities or "Blue Sky" laws
of the various states and jurisdictions of the United States or under any
foreign laws or regulations as the Depositor, on behalf of the Issuer Trust,
may deem necessary or desirable; and (iv) to execute, deliver and perform on
behalf of the Issuer Trust an underwriting agreement with one or more
underwriters relating to the offering of the Capital or Preferred Securities of
the Issuer Trust. In the event that any filing referred to in clauses (i), (ii)
or (iii) above is required by the rules and regulations of the Commission, the
New York Stock Exchange or such other exchanges or securities markets, the
NASD, or the securities or "Blue Sky" laws or foreign laws or regulations to be
executed on behalf of the Issuer Trust by the Administrators, the
Administrators, in their capacity as administrators of the Issuer Trust, are
hereby authorized and directed to join in any such filing and to execute on
behalf of the Issuer Trust any and all of the foregoing, it being understood
that the Administrators, in their capacity as administrators of the Issuer
Trust, shall not be required to join in any such filing or execute on behalf of
the Issuer Trust any such document unless required by the rules and regulations
of the Commission, the New York Stock Exchange or such other exchange or
securities markets, the NASD, or the securities or "Blue Sky" laws or foreign
laws or regulations.

         5. This Trust Agreement may be executed in one or more counterparts.

         6. The number of trustees and of administrators of the Issuer Trust
initially shall each be two and thereafter the number of trustees and
administrators of the Issuer Trust shall be such number as shall be fixed from
time to time by a written instrument signed by the Depositor, which may
increase or decrease the number of trustees and administrators of the Issuer


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Trust; provided, however, that, to the extent required by the Business Trust
Act, one trustee of the Issuer Trust shall either be a natural person who is a
resident of the State of Delaware or, if not a natural person, an entity which
has its principal place of business in the State of Delaware. Subject to the
foregoing, the Depositor is entitled to appoint or remove without cause any
trustee or administrator of the Issuer Trust at any time. Any trustee or
administrator of the Issuer Trust may resign upon thirty days' prior notice to
the Depositor.

         7. This Trust Agreement shall be governed by, and construed in
accordance with, the laws of the State of Delaware (without regard to conflict
of laws principles).

         IN WITNESS  WHEREOF,  the parties  hereto have caused this Trust
Agreement to be duly executed as of the day and year first above written.


                                            MORGAN STANLEY DEAN WITTER & CO.,
                                            as Depositor


                                            By: /s/ Alexander C. Frank
                                                -------------------------------
                                                Name:  Alexander C. Frank
                                                Title: Treasurer


                                            THE BANK OF NEW YORK (DELAWARE),
                                            not in its individual capacity but
                                            solely as Delaware Trustee


                                            By: /s/ William T. Lewis
                                                -------------------------------
                                                Name:  William T. Lewis
                                                Title: Senior Vice President


                                            THE BANK OF NEW YORK,
                                            not in its individual capacity but
                                            solely as Property Trustee


                                            By: /s/ Kisha Holder
                                                --------------------------------
                                                Name:  Kisha Holder
                                                Title: Assistant Treasurer






                                                /s/ Alexander C. Frank
                                                --------------------------------
                                                Name:  Alexander C. Frank
                                                Title: Administrator


                                                /s/ Debra M. Aaron
                                                --------------------------------
                                                Name:  Debra M. Aaron
                                                Title: Administrator