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                                                                    Exhibit 4.13


                                    GUARANTEE

                  For value received, UBS AG, a Swiss banking corporation
("UBS"), hereby unconditionally and irrevocably guarantees, as a primary obligor
and not merely as a surety, the obligations of UBS Americas Inc., a Delaware
corporation and the successor by merger to Paine Webber Group Inc. (the
"Company"), under the Amended and Restated Declaration of Trust of PWG Capital
Trust I, dated and effective as of December 9, 1996 (the "Declaration of
Trust"), by the trustees named therein, the Company and the holders from time to
time of undivided beneficial interests in the assets of PWG Capital Trust I
issued pursuant to the PWG I Declaration of Trust ("Holders of Outstanding
Securities"), including any amount as may be owed from time to time by the
Company under the Declaration of Trust, 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 Declaration of Trust.

                  UBS 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 Declaration of Trust, or otherwise) with respect to
the Declaration of Trust or any related agreement or instrument. If the Company
fails punctually to make any timely payment under the Declaration of Trust, UBS
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 maturity or by
declaration of acceleration, or otherwise, and as if such payment were made by
the Company.

                  UBS 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 Declaration of Trust, the absence of any
action to enforce the same or to collect from the Company, 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.
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                  UBS shall be subrogated to all rights of the Holders of
Outstanding Securities against the Company in respect of any amounts paid by UBS
pursuant to the provisions of this guarantee; provided, however, that UBS 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
outstanding Securities (as defined in the Declaration of Trust) shall have been
paid in full.

                  This guarantee shall bind UBS and its successors and assigns.
This guarantee constitutes a direct, unconditional and unsecured obligation of
UBS. The obligations of UBS hereunder will be subordinated in right of payment
to the prior payment in full of the deposit liabilities of UBS and all other
liabilities of UBS (including all deposit liabilities and other liabilities of
the head office and all offices of UBS wherever located), except (i) any
liabilities which by their terms rank pari passu with or are subordinated to the
obligations of UBS under this guarantee; (ii) any liabilities which by their
terms rank pari passu with or are subordinated to liabilities which by their
terms rank pari passu with or are subordinated to the obligations of UBS under
this guarantee; and (iii) any Existing Junior Subordinated Obligations. For the
avoidance of doubt, the obligations of UBS hereunder will be senior to any
Existing Junior Subordinated Obligations and any liabilities which by their
terms are subordinated to the obligations of UBS under this guarantee.

                  This guarantee shall be governed by the laws of the State of
New York, without regard to the principles of conflicts of laws thereof.
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                  IN WITNESS WHEREOF, UBS has caused this guarantee to be
executed by its duly authorized officers as of the day and year first above
written.


                                                     UBS AG

                                                     By: ____________________
                                                         Name:
                                                         Title:



                                                     By: ____________________
                                                         Name:
                                                         Title: