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                                                                    Exhibit 4.1e





                                UBS AMERICAS INC.
                             (as successor by merger
                          to Paine Webber Group Inc.),



                                UBS AG, GUARANTOR



                                       AND



                        THE CHASE MANHATTAN BANK, TRUSTEE




                          FOURTH SUPPLEMENTAL INDENTURE


                         Dated: as of December 22, 2000



                           Supplemental to Indenture,
                           dated as of March 15, 1988,

                                 as amended by,
                          First Supplemental Indenture,
                         dated as of September 22, 1989,

                         Second Supplemental Indenture,
                         dated as of March 22, 1991, and

                          Third Supplemental Indenture,
                          dated as of November 3, 2000

                                   relating to
                             Senior Debt Securities
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         FOURTH SUPPLEMENTAL INDENTURE, dated as of December -, 2000, among UBS
AMERICAS INC. (as successor by merger to Paine Webber Group Inc.), a Delaware
corporation (the "Company"), UBS AG, a Swiss banking corporation ("the
Guarantor"), and THE CHASE MANHATTAN BANK, a New York banking corporation (the
"Trustee").

                             RECITALS OF THE COMPANY

                  Pursuant to the Third Supplemental Indenture, dated as of
November 3, 2000 between Paine Webber Group Inc. ("PaineWebber") and the
Company, the Company succeeded to the obligations of PaineWebber under the
Indenture, dated as of March 15, 1988, between PaineWebber and the Trustee, as
supplemented by the First Supplemental Indenture dated as of September 22, 1989,
and the Second Supplemental Indenture dated as of March 22, 1991 (as amended by
such Supplemental Indentures, the "Senior Indenture"), pursuant to which
PaineWebber issued its outstanding unsecured debentures, notes or other
evidences of indebtedness (the "Outstanding Notes").

                  The Company has requested the Trustee and the Guarantor to
join with it in the execution and delivery of this fourth supplemental indenture
(the "Fourth Supplemental Indenture") in order to supplement and amend the
Senior Indenture, by amending and adding certain provisions thereof, to permit
the Company to accept the guarantee of the Guarantor of certain of the Company's
obligations.

                  The Company is a wholly owned subsidiary of the Guarantor, and
the Guarantor wishes to guarantee the Company's obligations pursuant to the
Senior Indenture and the Outstanding Notes.

                  The Company has authorized the execution and delivery of this
Fourth Supplemental Indenture by a Board Resolution, as defined in the Senior
Indenture.

                  The Guarantor has authorized the execution and delivery of
this Fourth Supplemental Indenture by a Board Resolution, as defined in the
Senior Indenture.

                  The Guarantor has authorized the execution and delivery of
this Fourth Supplemental Indenture by a
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resolution of or under the authority of its board of directors.

                  Section 901 of the Senior Indenture provides that a
supplemental indenture may be entered into by the Company and the Trustee,
without the consent of any Holders of the Outstanding Notes, to make any
provisions with respect to matters or questions arising under the Senior
Indenture, provided such action does not adversely affect the interests of the
Holders of Outstanding Notes of any series in any material respect.

                  The Company has determined that the execution and delivery of
this Fourth Supplemental Indenture by the Company, the Guarantor and the Trustee
complies with said Section 901 and does not require the consent of any Holder of
the Outstanding Notes.

                  At the request of the Trustee, the Company has furnished the
Trustee with an Opinion of Counsel complying with the requirements of Section
903 of the Senior Indenture, stating, among other things, that the execution of
this Fourth Supplemental Indenture is authorized or permitted by the Senior
Indenture, and an Officers' Certificate and Opinion of Counsel complying with
the requirements of Section 102 of the Senior Indenture, and has delivered to
the Trustee a Board Resolution as required by Section 901 of the Senior
Indenture authorizing the execution by the Company of this Fourth Supplemental
Indenture and its delivery by the Company to the Trustee.

                  All conditions and requirements necessary to make this Fourth
Supplemental Indenture a valid agreement of the Company, in accordance with the
terms of the Senior Indenture, and a valid amendment of and supplement to the
Indenture have been done.

                  NOW THEREFORE, the Company, the Guarantor and the Trustee
hereby agree as follows:

I.  Amendments to the Senior Indenture


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                  1. Section 101 of the Senior Indenture is hereby amended by
the insertion of the following definitions in the appropriate alphabetical
order:

                           "Guarantor" means UBS AG, a Swiss banking
         corporation, until a successor Person shall have become such pursuant
         to the applicable provisions of this Indenture and thereafter
         "Guarantor" shall mean such successor Person.

                           "Guarantor Order" means a written order signed in the
         name of the Guarantor by its Chairman of the Board, its President or a
         Vice President, and by its Treasurer, an Assistant Treasurer, its
         Controller, an Assistant Controller, its Secretary or an Assistant
         Secretary, and delivered to the Trustee.

                           "Guarantee" means the Guarantor's unconditional
         guarantee of the payment of the Securities, as provided in Article
         Three-A.

                  2. The definition of "Officer's Certificate" in Section 101 of
the Senior Indenture is hereby amended and restated in its entirety as follows:

                           "Officers' Certificate" means, (i) with respect to
         the Company, a certificate signed by the Chairman of the Board, the
         Vice Chairman of the Board, the President or any Vice President, and by
         the Treasurer, the Controller, the Secretary or any Assistant
         Treasurer, Assistant Controller or Assistant Secretary, of the Company,
         and delivered to the Trustee; and (ii) with respect to the Guarantor, a
         certificate signed by two persons authorized to bind the Guarantor, and
         delivered to the Trustee. Each such Officers' Certificate shall contain
         the statements provided in Section 102, if applicable.

                  3. The definition of "Opinion of Counsel" in Section 101 of
the Senior Indenture is hereby amended and restated in its entirety as follows:


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                           "Opinion of Counsel" means a written opinion of
         counsel, who may be counsel for or an employee of the Company or the
         Guarantor and who shall be acceptable to the Trustee. Each Opinion of
         Counsel shall contain the statements provided in Section 102, if
         applicable.

                  4. The Senior Indenture is hereby amended by the insertion of
the following Article Three-A after the existing Article Three:

                                 ARTICLE THREE-A

                                  The Guarantee

Section 301-A.  Unconditional Guarantee.

                  For value received, the Guarantor hereby unconditionally and
irrevocably guarantees, as a primary obligor and not merely as a surety, for the
benefit of the Holders of the Securities, all the obligations of the Company
under the Indenture and the Securities, including the due and punctual payment
of the principal of (and premium, if any) and interest on the Securities
(including any additional interest or other amounts payable in accordance with
the terms of the Securities) together with any other amount as may be owed from
time to time by the Company under the Indenture where, when and as the same
shall become due and payable, whether at maturity, upon acceleration, redemption
or otherwise in accordance with the terms of the Securities. The Guarantor
hereby waives presentment, demand for payment, protest and acceptance of this
guarantee and all notices to any person (whether of nonpayment, dishonor,
protest, extension of credit to the debtor or of other matters referred to in
the Indenture, or otherwise) with respect to the Securities or the Indenture or
any other related agreement or instrument. If the Company fails punctually to
pay any such principal (and premium, if any) or interest, the Guarantor hereby
agrees to cause any such payment to be made punctually when and as the same
shall become due and payable, whether at the stated

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maturity or by declaration of acceleration, or otherwise, and as if such payment
were made by the Company.

                  The Guarantor hereby agrees that this guarantee is an
absolute, present and continuing guarantee of payment and not of collectability
and that its obligations hereunder shall be unconditional, irrespective of the
validity, legality or enforceability of the Securities or the Indenture, the
absence of any action to enforce the same or to collect from the Company, any
waiver or consent by the holder of the Securities with respect to the provisions
thereof, and the recovery of any judgment against the Company or any action to
enforce the same or any other circumstance that might otherwise result in a
legal or equitable discharge or defense of a guarantor.

                  The Guarantor shall be subrogated to all rights of the Holders
of any Security against the Company in respect of any amounts paid by the
Guarantor pursuant to the provisions of the Guarantee; provided, however, that
the Guarantor shall not be entitled to enforce or to receive any payments
arising out of, or based upon, such right of subrogation until the principal of
and interest on all Securities issued hereunder shall have been paid in full.

                  This guarantee shall bind the Guarantor and its successors and
assigns. This guarantee constitutes a direct, unconditional and unsecured
obligation of the Guarantor.

                  5. Section 502 of the Senior Indenture is hereby amended by
inserting the words "or the Guarantor" after the word "Company" in subparagraph
(1) thereof.

                  6. Section 503 of the Senior Indenture is hereby amended by
inserting a comma and then the words "the Guarantor" in the penultimate
paragraph following the word "Company" the second and third times the word
"Company" appears.

                  7. Section 504 of the Senior Indenture is hereby amended by
(i) inserting a comma and then the words "the

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Guarantor" in the first paragraph the first and second times the word "Company"
appears, in each case following the word "Company" and (ii) inserting the words
"or the Guarantor" the third time the word "Company" appears, following the word
"Company".

                  8. Section 515 of the Senior Indenture is hereby amended by
inserting the words "and the Guarantor each" following the word "Company" in
each case where the word "Company" appears.

                  9. Section 607 of the Senior Indenture is hereby amended by
(i) inserting the words "and the Guarantor" following the word "Company" in the
first line thereof, (ii) replacing the word "agrees" with the word "agree" in
the first line thereof, and (iii) inserting the words "and the Guarantor"
following the word "Company" in the final paragraph thereof.

                  10. The Senior Indenture is hereby amended by the insertion of
the following paragraphs at the end of Article Eight:

Section 803.      Guarantor May Consolidate, Etc., Only on
                  Certain Terms.

                  The Guarantor shall not consolidate with or merge into any
other corporation or convey, transfer or lease its properties and assets
substantially as an entirety to any Person, and the Guarantor shall not permit
any Person to consolidate with or merge into the Guarantor or convey, transfer
or lease its properties and assets substantially as an entirety to the
Guarantor, unless:

                  (1) in case the Guarantor shall consolidate with or merge into
         another corporation or convey, transfer or lease its properties and
         assets substantially as an entirety to any Person, the corporation
         formed by such consolidation or into which the Guarantor is merged or
         the Person which acquires by conveyance or transfer, or which leases,
         the properties and assets of the Guarantor substantially as an entirety
         shall be a



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         corporation organized and existing under the laws of Switzerland or any
         other country, or any state or subdivision thereof or therein, and
         shall expressly assume, by an indenture supplemental hereto, executed
         and delivered to the Trustee, in form satisfactory to the Trustee, the
         performance of Guarantee and the performance of every covenant of this
         Indenture on the part of the Guarantor to be performed or observed;

                  (2) immediately after giving effect to such transaction and
         treating any indebtedness which becomes an obligation of the Company or
         a Subsidiary (as defined in Section 1009) as a result of such
         transaction as having been incurred by the Company or such Subsidiary
         at the time of such transaction, no Event of Default, and no event
         which, after notice or lapse of time or both, would become an Event of
         Default, shall have happened and be continuing; and

                  (3) if a supplemental indenture is required in connection with
         such transaction, the Guarantor shall have delivered to the Trustee an
         Officers' Certificate and an Opinion of Counsel, each stating that such
         consolidation, merger, conveyance, transfer or lease and such
         supplemental indenture comply with this Article and that all conditions
         precedent herein provided for relating to such transaction have been
         complied with.

Section 804. Successor Substituted.

                  Upon any consolidation of the Guarantor with or merger by the
Guarantor into any other corporation or any conveyance, transfer or lease of the
properties and assets of the Guarantor substantially as an entirety in
accordance with Section 803, the successor corporation formed by such
consolidation or into which the Guarantor is merged or to which such conveyance,
transfer or lease is made shall succeed to, and be substituted for, and may
exercise every right and power of, the Guarantor under this Indenture with the
same effect as if such successor corporation had been named as the Guarantor
herein, and thereafter, except in the

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case of such lease, the predecessor corporation shall be relieved of all
obligations and covenants under this Indenture and the Guarantee.

                  11. Section 901 of the Senior Indenture is hereby amended by
inserting the words "or the Guarantor" after the word "Company" in subparagraph
(1) thereof in each case where the word "Company" appears.

                  12. The penultimate paragraph of Section 1003 of the Senior
Indenture is hereby amended by (i) inserting the words "or the Guarantor" after
the words "The Company" at the beginning of such paragraph, and (ii) inserting
the words "or Guarantor Order, as the case may be" after the words "Company
Order."

                  13. Ratification and Confirmation. As amended and modified by
this Fourth Supplemental Indenture, the Senior Indenture is in all respects
ratified and confirmed and the Senior Indenture and this Fourth Supplemental
Indenture shall be read, taken and construed as one and the same instrument.

                  14. Counterparts. This Fourth Supplemental Indenture may be
executed in any number of counterparts and all said counterparts executed and
delivered each as an original shall constitute but one and the same instrument.

                  15. Trustee's Duties, Responsibilities and Liabilities. The
recitals contained herein shall be taken as the statements of the Company and
the Guarantor, and the Trustee assumes no responsibility for the correctness of
same. The Trustee makes no representation as to the validity of this Fourth
Supplemental Indenture. The Trustee assumes no duties, responsibilities or
liabilities by reason of this Fourth Supplemental Indenture other than as set
forth in the Senior Indenture, and this Fourth Supplemental Indenture is
executed and accepted by the Trustee subject to all the terms and conditions of
its acceptance of the trust under the Senior Indenture, as fully as if said
terms and conditions were herein set forth at length.


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                  IN WITNESS WHEREOF, the parties hereto have caused this Fourth
Supplemental Indenture to be duly executed, and their respective corporate seals
to be hereunto affixed and attested, as of the day and year first above written.

                                  UBS AMERICAS INC.
                                  (as successor by merger to
                                  Paine Webber Group Inc.)



                                  By:
                                           -------------------------
                                           Name:
                                           Title:
ATTEST:



------------------------------
Name:
Title:
                                  UBS AG




                                  By:
                                           -------------------------
                                           Name:
                                           Title:
ATTEST:




------------------------------
Name:
Title:
                                  THE CHASE MANHATTAN BANK



                                  By:
                                           -------------------------
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                                           Name:
                                           Title
ATTEST:



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Name:
Title: