1
                                                                     Exhibit 5.1


                        [RICHARDS, LAYTON & FINGER, P.A.]







                               September 29, 2000




UBS Preferred Funding Company LLC I
c/o UBS AG
299 Park Avenue
New York, New York 10171

UBS Preferred Funding Trust I
c/o UBS AG
299 Park Avenue
New York, New York 10171

         Re:  UBS Preferred Funding Company LLC I
              and UBS Preferred Funding Trust I

Ladies and Gentlemen:

         We have acted as special Delaware counsel for UBS Preferred Funding
Company LLC I, a Delaware limited liability company (the "Company"), and UBS
Preferred Funding Trust I, a Delaware business trust (the "Trust"), in
connection with the matters set forth herein. At your request, this opinion is
being furnished to you.

         For purposes of giving the opinions hereinafter set forth, our
examination of documents has been limited to the examination of originals or
copies of the following:

         (a) The Certificate of Formation of the Company, dated as of September
18, 2000 (the "LLC Certificate"), as filed in the office of the Secretary of
State of the State of Delaware (the "Secretary of State") on September 18, 2000;

         (b) The Limited Liability Company Agreement of the Company, dated as of
September 18, 2000, entered into by UBS AG, a bank organized under the laws of
Switzerland ("UBS");

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UBS Preferred Funding Company LLC I
UBS Preferred Funding Trust I
September 29, 2000
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         (c) A form of Amended and Restated Limited Liability Company Agreement
of the Company (the "LLC Agreement"), to be entered into by UBS and the Trust,
as members, to be attached as an exhibit to the Registration Statement (as
defined below);

         (d) The Certificate of Trust of the Trust (the "Trust Certificate"), as
filed in the office of the Secretary of State on September 18, 2000;

         (e) The Trust Agreement of the Trust, dated as of September 18, 2000,
between the Company, as grantor, and Wilmington Trust Company, as trustee of the
Trust (the "Trustee");

         (f) A form of the Amended and Restated Trust Agreement of the Trust
(the "Trust Agreement"), to be entered into among the Company, as guarantor, the
Trustee and UBS, solely for the purposes stated therein, to be attached as an
exhibit to the Registration Statement;

         (g) The Registration Statement (the "Registration Statement") on Form
F-1 Registration No. 333-46216, including a related prospectus (the
"Prospectus"), relating to the ___% Noncumulative Company Preferred Securities
of the Company (each, a "Preferred Security" and collectively, the "Preferred
Securities") and to the ___% Noncumulative Trust Preferred Securities of the
Trust (each, a "Trust Preferred Security" and collectively, the "Trust Preferred
Securities"), as filed by the Company and the Trust with the Securities and
Exchange Commission on or about September 20, 2000;

         (h) A Certificate of Good Standing for the Company, dated September 28,
2000, obtained from the Secretary of State; and

         (i) A Certificate of Good Standing for the Trust, dated September 28,
2000, obtained from the Secretary of State.

         Initially capitalized terms used herein and not otherwise defined are
used as defined in the LLC Agreement.

         For purposes of this opinion, we have not reviewed any documents other
than the documents listed in paragraphs (a) through (i) above. In particular, we
have not reviewed any document (other than the documents listed in paragraphs
(a) through (i) above) that is referred to in or incorporated by reference into
the documents reviewed by us. We have assumed that there exists no provision in
any document that we have not reviewed that is inconsistent with the opinions
stated herein. We have conducted no independent factual investigation of our
own, but rather have relied solely upon the foregoing documents, the statements
and information set forth therein and the additional matters recited or assumed
herein, all of which we have assumed to be true, complete and accurate in all
material respects.
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UBS Preferred Funding Company LLC I
UBS Preferred Funding Trust I
September 29, 2000
Page 3


         With respect to all documents examined by us, we have assumed (i) the
authenticity of all documents submitted to us as authentic originals, (ii) the
conformity with the originals of all documents submitted to us as copies or
forms, and (iii) the genuineness of all signatures.

         For purposes of this opinion, we have assumed (i) that the LLC
Agreement constitutes the entire agreement among the parties thereto with
respect to the subject matter thereof, including with respect to the admission
of members to, and the creation, operation, management and termination of, the
Company, and that the LLC Agreement and the LLC Certificate are in full force
and effect and have not been amended, (ii) that the Trust Agreement constitutes
the entire agreement among the parties thereto with respect to the subject
matter thereof, including with respect to the creation, operation, management
and termination of the Trust, and that the Trust Agreement and the Trust
Certificate are in full force and effect and have not been amended, (iii) except
to the extent provided in paragraphs 1 and 4 below, the due creation or the due
organization or due formation, as the case may be, and valid existence in good
standing of each party to the documents examined by us under the laws of the
jurisdiction governing its creation or organization or formation, (iv) the legal
capacity of natural persons who are signatories to the documents examined by us,
(v) that each of the parties to the documents examined by us has the power and
authority to execute and deliver, and to perform its obligations under, such
documents, (vi) the due authorization, execution and delivery by all parties
thereto of all documents examined by us, (vii) the receipt by each Person to
whom a Preferred Security is to be issued by the Company (each, a "Preferred
Securityholder" and collectively, the "Preferred Securityholders") of a
certificate substantially in the form of the certificate attached to the LLC
Agreement evidencing the Preferred Securities and the payment for the Preferred
Securities acquired by it, in accordance with the LLC Agreement and the
Registration Statement, (viii) the receipt by each Person to whom a Trust
Preferred Security is to be issued by the Trust (each, a "Holder" and
collectively, the "Holders") of a certificate substantially in the form of the
trust certificate attached to the Trust Agreement and the payment for the Trust
Preferred Security acquired by it, in accordance with the Trust Agreement and
the Registration Statement, (ix) that the books and records of the Company set
forth the names and addresses of all Persons to be admitted as members of the
Company and the dollar value of each of the member's contribution to the
Company, (x) that the Preferred Securities are issued and sold to the Preferred
Securityholders in accordance with the Registration Statement and the LLC
Agreement, and (xi) that the Trust Preferred Securities are issued and sold to
the Holders in accordance with the Registration Statement and the Trust
Agreement. We have not participated in the preparation of the Registration
Statement and assume no responsibility for its contents.

         This opinion is limited to the laws of the State of Delaware (excluding
the securities laws and blue sky laws of the State of Delaware), and we have not
considered and express no opinion on the laws of any other jurisdiction,
including federal laws and rules and regulations relating thereto. Our opinions
are rendered only with respect to Delaware laws and rules, regulations and
orders thereunder which are currently in effect.
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UBS Preferred Funding Company LLC I
UBS Preferred Funding Trust I
September 29, 2000
Page 4


         Based upon the foregoing, and upon our examination of such questions of
law and statutes of the State of Delaware as we have considered necessary or
appropriate, and subject to the assumptions, qualifications, limitations and
exceptions set forth herein, we are of the opinion that:

         1. The Company has been duly formed and is validly existing in good
standing as a limited liability company under the Delaware Limited Liability
Company Act (6 Del. C. Section 18- 101, et seq.).

         2. The Preferred Securities will represent valid and, subject to the
qualifications set forth in paragraph 3 below, fully paid and nonassessable
limited liability company interest in the Company.

         3. The Preferred Securityholders shall not be obligated personally for
any of the debts, obligations or liabilities of the Company, whether arising in
contract, tort or otherwise solely by reason of being a member of the Company,
except as a Preferred Securityholder may be obligated to repay any funds
wrongfully distributed to it. We note that the Preferred Securityholders may be
obligated to make payments as set forth in the LLC Agreement.

         4. The Trust has been duly created and is validly existing in good
standing as a business trust under the Delaware Business Trust Act (12 Del. C.
Section 3801, et seq.).

         5. The Trust Preferred Securities will represent valid and, subject to
the qualifications set forth in paragraph 6 below, fully paid and nonassessable
interests in the Trust.

         6. The Holders, in their capacity as such, will be entitled to the same
limitation of personal liability extended to stockholders of private
corporations for profit organized under the General Corporation Law of the State
of Delaware. We note that the Holders may be obligated to make payments as set
forth in the Trust Agreement.

         We consent to the filing of this opinion with the Securities and
Exchange Commission as an exhibit to the Registration Statement. We also consent
to Sullivan & Cromwell's and Davis Polk & Wardwell's relying as to matters of
Delaware law upon this opinion in connection with opinions to be rendered by
them in connection with the Registration Statement. In addition, we hereby
consent to the use of our name under the heading "Validity of the Securities" in
the Prospectus. In giving the foregoing consents, we do not thereby admit that
we come within the category of Persons whose consent is required under Section 7
of the

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UBS Preferred Funding Company LLC I
UBS Preferred Funding Trust I
September 29, 2000
Page 5


Securities Act of 1933, as amended, or the rules and regulations of the
Securities and Exchange Commission thereunder. Except as stated above, without
our prior written consent, this opinion may not be furnished or quoted to, or
relied upon by, any other Person for any purpose.


                                       Very truly yours,

                                       /s/ Richards, Layton & Finger, P.A.

EAM/JGL/ENF