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                                                                    Exhibit 8.1

                        [SULLIVAN & CROMWELL LETTERHEAD]



                                                                 March 29, 2001


UBS AG
  Bahnhofstrasse 45,
    CH-8098 Zurich,
      Switzerland.


UBS Americas, Inc.,
  677 Washington Boulevard,
    Stamford, Connecticut, 06901


Ladies and Gentlemen:


     We have acted as your counsel in connection with the registration under
the Securities Act of 1933 (the "Act") of certain debt securities of UBS
Americas, Inc. (the "Company) set forth on Annex A. We hereby confirm to you
that our opinion is as set forth under the caption "Certain United States
Federal Income Tax Considerations" in the prospectus dated March 29, 2001 (the
"Prospectus"), included in the related Registration Statement on Form F-1 filed
by


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the Company with the Securities and Exchange Commission (the "Registration
Statement").

     We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to us under the heading "Certain
United States Federal Income Tax Considerations" the Prospectus. In giving such
consent, we do not admit that we are in the category of persons whose consent
is required under Section 7 of the Act.


                                       Very truly yours,


                                       /s/ Sullivan & Cromwell
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                                    Annex A

$150,000,000 of 9 1/4% Notes Due 2001

$100,000,000 of 7 7/8% Notes Due 2003

$200,000,000 of 6 1/2% Notes Due 2005

$100,000,000 of 6 3/4% Notes Due 2006

$200,000,000 of 7 5/8% Notes Due 2014

$125,000,000 of 8 7/8% Notes Due 2005

$125,000,000 of 8 1/4% Notes Due 2002

$150,000,000 of 7 5/8% Notes Due 2008

$250,000,000 of 6.55% Notes Due 2008

$340,000,000 of 6.45% Notes Due 2003

$525,000,000 of 6 3/8% Notes Due 2004

$275,000,000 of 7 5/8% Notes Due 2009

$175,000,000 of 7 3/4% Subordinated Notes Due 2002

Medium-Term Senior Notes, Series C

Medium-Term Subordinated Notes, Series D