<PAGE>   1
    AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON NOVEMBER 3, 2000
                                                      REGISTRATION NO. 333-_____


                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                               ------------------


                                    FORM S-8

                             REGISTRATION STATEMENT
                                    UNDER THE
                             SECURITIES ACT OF 1933

                                     UBS AG
             (Exact Name of Registrant as Specified in Its Charter)

                                   SWITZERLAND
         (State or Other Jurisdiction of Incorporation or Organization)

                                   98-0186363
                     (I.R.S. Employer Identification Number)

         BAHNHOFSTRASSE 45, ZURICH, SWITZERLAND, AND AESCHENVORSTADT 1,
                               BASEL, SWITZERLAND
                    (Address of Principal Executive Offices)

              UBS AG/PAINE WEBBER GROUP INC. REPLACEMENT STOCK PLAN
                            (Full Title of the Plan)

                           ROBERT C. DINERSTEIN, ESQ.
                                     UBS AG
                                 299 PARK AVENUE
                            NEW YORK, NEW YORK 10171
                                 (212) 821-3000
            (Name, Address and Telephone Number of Agent for Service)

                                   COPIES TO:
                              H. RODGIN COHEN, ESQ.
                            REBECCA J. SIMMONS, ESQ.
                               SULLIVAN & CROMWELL
                                125 BROAD STREET
                            NEW YORK, NEW YORK 10004
                                 (212) 558-4000

                         CALCULATION OF REGISTRATION FEE


<TABLE>
<CAPTION>
                                                         PROPOSED MAXIMUM     PROPOSED MAXIMUM      AMOUNT OF
  TITLE OF EACH CLASS OF                                OFFERING PRICE PER   AGGREGATE OFFERING   REGISTRATION
SECURITIES TO BE REGISTERED   AMOUNT TO BE REGISTERED        SHARE(1)             PRICE (1)          FEE (1)
<S>                           <C>                       <C>                  <C>                  <C>
ORDINARY SHARES PAR VALUE      6,365,890                Not Applicable       $855,893,910.50      $225,956
CHF 10
</TABLE>

      (1)  PURSUANT TO RULE 457(h)(1) AND 457(c) OF THE SECURITIES ACT OF 1933,
           AS AMENDED, THE PROPOSED MAXIMUM OFFERING PRICE AND THE AMOUNT OF
           THE REGISTRATION FEE HAVE BEEN COMPUTED ON THE BASIS OF A PRICE OF
           $134.45 PER UBS AG ORDINARY SHARE, THE AVERAGE OF THE HIGH AND LOW
           SALE PRICES PER UBS AG ORDINARY SHARE ON THE NEW YORK STOCK EXCHANGE
           COMPOSITE TAPE ON OCTOBER 27, 2000.





<PAGE>   2
                                     PART I


              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

                                EXPLANATORY NOTE


           As permitted by Rule 428 under the Securities Act of 1933, as
amended, this registration statement omits the information specified in Part I
of Form S-8. The documents containing the information specified in Part I will
be delivered to the participants in the plan covered by this registration
statement, as required by Rule 428(b). Such documents are not being filed with
the Securities and Exchange Commission as part of this registration statement or
as prospectuses or prospectus supplements pursuant to Rule 424 of the Securities
Act.






                                       -1-
<PAGE>   3
                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.          INCORPORATION OF DOCUMENTS BY REFERENCE

         The following documents filed by UBS AG (the "Company") are hereby
incorporated by reference in this registration statement:

         The Company's Annual Report on Form 20-F for the year ended December
31, 1999, filed pursuant to the Securities Exchange Act of 1934 (the "Exchange
Act"), as amended or supplemented by the prospectus filed by the Company
pursuant to Rule 424(b)(1) on October 3, 2000;

         The Company's reports on Form 6-K filed on May 25, 2000, July 12, 2000,
July 17, 2000, July 26, 2000, October 2, 2000, October 11, 2000 October 24, 2000
and October 27, 2000 filed pursuant to the Exchange Act;

         The description of the Company's Ordinary Shares, par value CHF 10 per
share, contained in the Company's registration statement on Form 20-F filed with
the Commission on May 9, 2000, pursuant to the Exchange Act (Registration No.
00115026) including any amendments or reports filed for the purposes of updating
such description; and

         All documents filed by the Company pursuant to Section 13(a) and 15(d)
of the Exchange Act of 1934, as amended, after the date of this registration
statement and prior to the filing of a post-effective amendment to this
registration statement which indicates that all securities offered hereby have
been sold or which deregisters all securities then remaining unsold, shall be
deemed to be incorporated by reference in this registration statement and to be
a part hereof from the filing date of such documents.

         Any statement contained in a document incorporated or deemed to be
incorporated by reference herein shall be deemed to be modified or superseded
for purposes of this registration statement to the extent that a statement
contained herein (or in any other subsequently filed document which also is
incorporated or deemed to be incorporated by reference herein) modifies or
supersedes such statement. Any such statement so modified or superseded shall
not be deemed, except as so modified or superseded, to constitute a part of this
registration statement.

ITEM 4.         DESCRIPTION OF SECURITIES

                Not applicable.


ITEM 5.         INTERESTS OF NAMED EXPERTS AND COUNSEL

                Not applicable.



                                       -2-
<PAGE>   4
ITEM 6.         INDEMNIFICATION OF DIRECTORS AND OFFICERS

         Neither the UBS articles of association nor Swiss statutory law contain
provisions regarding the indemnification of directors and officers.

         According to general principles of Swiss employment law, an employer
may, under certain circumstances, be required to indemnify an employee against
losses and expenses incurred by him in the execution of his duties under the
employment agreement, unless the losses and expenses arise from the employee's
gross negligence or willful misconduct.

         UBS maintains directors' and officers' insurance for its directors and
officers.

ITEM 7.         EXEMPTION FROM REGISTRATION CLAIMED

                Not applicable.

ITEM 8.         EXHIBITS

Exhibit
  No.           Description

4.1             Articles of Association of UBS AG.

4.2             Organization Regulations of UBS AG.

5               Opinion of Baer & Karrer, Swiss counsel of UBS AG, regarding
                validity of the securities of UBS AG being registered under this
                Registration Statement.

23.1            Consent of Ernst & Young Ltd.

23.2            Consent of Baer & Karrer (Included in Exhibit 5 to this
                registration statement).

24              Power of Attorney.

ITEM 9.         UNDERTAKINGS

The undersigned registrant hereby undertakes:

(1) To file, during any period in which offers or sales are being made, a
post-effective amendment to this registration statement:

            (i)       To include any prospectus required by Section 10(a)(3) of
                      the Securities Act.

           (ii)       To reflect in the prospectus any facts or events arising
                      after the effective date of this registration statement
                      (or the most recent post-effective amendment thereof)
                      which, individually or in aggregate, represent a
                      fundamental change in the information set forth in this
                      registration statement. Notwithstanding the



                                       -3-
<PAGE>   5
                      foregoing, any increase or decrease in volume of
                      securities offered (if the total dollar value of
                      securities offered would not exceed that which was
                      registered) and any deviation from the low or high end of
                      the estimated maximum offering range may be reflected in
                      the form of prospectus filed with the Commission pursuant
                      to Rule 424(b) if, in the aggregate, the changes in volume
                      and price represent no more than 20 percent change in the
                      maximum aggregate offering price set forth in the
                      "Calculation of Registration Fee" table in the effective
                      registration statement.

           (iii)      To include any material information with respect to the
                      plan of distribution not previously disclosed in this
                      registration statement or any material change to such
                      information in this registration statement;

                      provided, however, that paragraphs (a)(1)(i) and
                      (a)(1)(ii) of this Item 9 do not apply if the information
                      required to be included in the post-effective amendment by
                      those paragraphs is contained in periodic reports filed by
                      the Company pursuant to Section 13 or Section 15(d) of the
                      Exchange Act that are incorporated by reference in this
                      registration statement.

(2) That, for the purpose of determining any liability under the Securities Act,
each such post-effective amendment shall be deemed to be a new registration
statement relating to the securities offered therein, and the offering of such
securities at that time shall be deemed to be the initial bona fide offering
thereof.

(3) To remove from registration by means of a post-effective amendment any of
the securities being registered which remain unsold at the termination of the
offering.

(4) To file a post-effective amendment to the registration statement to include
any financial statements required by Item 8.A. of Form 20-F at the start of any
delayed offering or throughout a continuous offering. Financial statements and
information otherwise required by Section 10 (a) (3) of the Act need not be
furnished, provided, that the registrant includes in the prospectus, by means of
a post-effective amendment, financial statements required pursuant to this
paragraph (a) (4) and other information necessary to ensure that all other
information in the prospectus is at least as current as the date of those
financial statements. Notwithstanding the foregoing, with respect to
registration statements on Form F-3, a post-effective amendment need not be
filed to include financial statements and information required by Section 10(a)
(3) of the Act or Rule 3-19 of this chapter if such financial statements and
information are contained in periodic reports filed with or furnished to the
Commission by the registrant pursuant to Section 13, or Section 15 (d) of the
Securities Exchange Act of 1934, as amended, that are incorporated by reference
in the Form F-3.

(5) The undersigned Company hereby undertakes that, for purposes of determining
any liability under the Securities Act, each filing of the Company's annual
report pursuant to Section 13(a) or 15(d) of the Exchange Act (and, where
applicable, each filing of an employee benefit plan's annual report pursuant to
Section 15(d) of the Exchange Act) that is incorporated by reference in this
registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.




                                       -4-
<PAGE>   6
(6) Insofar as indemnification for liabilities arising under the Securities Act
of 1933, as amended, may be permitted to directors, officers and controlling
persons of the Company pursuant to the foregoing provisions, or otherwise, the
Company has been advised that in the opinion of the Securities and Exchange
Commission such indemnification is against public policy as expressed in the Act
and is, therefore, unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the Company of expenses
incurred or paid by a director, officer or controlling person of the Company in
the successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Company will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Act and will be governed by the final adjudication of
such issue.








                                       -5-
<PAGE>   7
                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, as amended,
the Company certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
registration statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Zurich, Switzerland, on November 3, 2000.

                           UBS AG


                           By: /s/ Luqman Arnold
                               -----------------------------------------
                           Name:  Luqman Arnold
                           Title: Chief Financial Officer


                           By: /s/ Robert B. Mills
                               -----------------------------------------
                           Name:  Robert B. Mills
                           Title: Managing Director

         Pursuant to the requirements of the Securities Act of 1933, as amended,
this registration statement has been signed by the following persons in the
indicated capacities on November 3, 2000.

<TABLE>
<CAPTION>
Name                                      Title
----                                      -----

<S>                                       <C>
by:            *                          President and Group
      ---------------------------         Chief Executive Officer
Name: Marcel Ospel                        (Principal Executive Officer)

by:            *                          Chief Financial Officer
      ---------------------------         (Principal Financial Officer)
Name: Luqman Arnold

by:            *                          Group Controller
      ---------------------------         and Member of Group Managing Board
Name: Hugo Schaub                         (Principal Accounting Officer)

by:            *                          Chairman of the Board of Directors
      ---------------------------
Name: Alex Krauer

by:            *                          Vice Chairman of the Board of Directors
      ---------------------------
Name: Alberto Togni

by:            *                          Vice Chairman of the Board of Directors
      ---------------------------
Name: Markus Kundig
</TABLE>




                                       -6-
<PAGE>   8
<TABLE>
<CAPTION>
Name                                      Title
----                                      -----

<S>                                       <C>
by:               *                       Member of the Board of Directors
      ---------------------------
Name: Peter Bockli

by:               *                       Member of the Board of Directors
      ---------------------------
Name: Eric Honegger

by:               *                       Member of the Board of Directors
      ---------------------------
Name: Rolf A. Meyer

by:               *                       Member of the Board of Directors
      ---------------------------
Name: Hans Peter Ming

by:                                       Member of the Board of Directors
      ---------------------------
Name: Andreas Reinhart
</TABLE>


*  By Power of Attorney




  /s/ Luqman Arnold
  -----------------------------------------
  Luqman Arnold






                                       -7-
<PAGE>   9
         Pursuant to the requirements of Section 6(a) of the Securities Act of
1933, as amended, the Authorized Representative has duly caused this
Registration Statement to be signed on its behalf by the undersigned, solely in
its capacity as the duly authorized representative of UBS AG in the United
States, in The City of New York, State of New York, on the 3rd of November,
2000.





                                        By: /s/ Robert B. Mills
                                            -----------------------
                                        Name:  Robert B. Mills
                                        Title: Managing Director






                                       -8-
<PAGE>   10
                                INDEX TO EXHIBITS

4.1            Articles of Association of UBS AG.

4.2            Organization Regulations of UBS AG.

5              Opinion of Baer & Karrer, Swiss counsel of UBS AG, regarding
               validity of the securities of UBS AG being registered under this
               Registration Statement.

23.1           Consent of Ernst & Young Ltd.

23.2           Consent of Baer & Karrer (Included in Exhibit 5 to this
               registration statement).

24             Power of Attorney.




                                       -9-
[{"type": "S-8", "sequence": "1", "filename": "y41943s-8.txt", "description": "FORM S-8", "secsgml_size_bytes": 18071}]
{"company-data": {"conformed-name": "UBS AG", "cik": "0001114446", "assigned-sic": "6021", "irs-number": "000000000", "state-of-incorporation": "V8", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-49210", "film-number": "752325"}, "business-address": {"street1": "BAHNHOFSTRASSE 45", "city": "ZURICH SWITZERLAND", "state": "V8", "zip": "00000", "phone": "212-821-3000"}, "mail-address": {"street1": "BAHNHOFSTRASSE 45", "street2": "ZURICH", "city": "ZURICH SWITZERLAND", "state": "V8", "zip": "00000"}}
1
    AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON NOVEMBER 3, 2000
                                                      REGISTRATION NO. 333-_____

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                               ------------------

                                    FORM S-8

                             REGISTRATION STATEMENT
                                    UNDER THE
                             SECURITIES ACT OF 1933

                                     UBS AG
             (Exact Name of Registrant as Specified in Its Charter)

                                   SWITZERLAND
         (State or Other Jurisdiction of Incorporation or Organization)

                                   98-0186363
                     (I.R.S. Employer Identification Number)

         BAHNHOFSTRASSE 45, ZURICH, SWITZERLAND, AND AESCHENVORSTADT 1,
                               BASEL, SWITZERLAND
                    (Address of Principal Executive Offices)

              UBS AG/PAINE WEBBER GROUP INC. REPLACEMENT STOCK PLAN
                            (Full Title of the Plan)

                           ROBERT C. DINERSTEIN, ESQ.
                                     UBS AG
                                 299 PARK AVENUE
                            NEW YORK, NEW YORK 10171
                                 (212) 821-3000
            (Name, Address and Telephone Number of Agent for Service)

                                   COPIES TO:
                              H. RODGIN COHEN, ESQ.
                            REBECCA J. SIMMONS, ESQ.
                               SULLIVAN & CROMWELL
                                125 BROAD STREET
                            NEW YORK, NEW YORK 10004
                                 (212) 558-4000

                         CALCULATION OF REGISTRATION FEE
PROPOSED MAXIMUM     PROPOSED MAXIMUM      AMOUNT OF
  TITLE OF EACH CLASS OF                                OFFERING PRICE PER   AGGREGATE OFFERING   REGISTRATION
SECURITIES TO BE REGISTERED   AMOUNT TO BE REGISTERED        SHARE(1)             PRICE (1)          FEE (1)
ORDINARY SHARES PAR VALUE      6,365,890                Not Applicable       $855,893,910.50      $225,956
CHF 10
(1)  PURSUANT TO RULE 457(h)(1) AND 457(c) OF THE SECURITIES ACT OF 1933,
           AS AMENDED, THE PROPOSED MAXIMUM OFFERING PRICE AND THE AMOUNT OF
           THE REGISTRATION FEE HAVE BEEN COMPUTED ON THE BASIS OF A PRICE OF
           $134.45 PER UBS AG ORDINARY SHARE, THE AVERAGE OF THE HIGH AND LOW
           SALE PRICES PER UBS AG ORDINARY SHARE ON THE NEW YORK STOCK EXCHANGE
           COMPOSITE TAPE ON OCTOBER 27, 2000.
2
                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

                                EXPLANATORY NOTE

           As permitted by Rule 428 under the Securities Act of 1933, as
amended, this registration statement omits the information specified in Part I
of Form S-8. The documents containing the information specified in Part I will
be delivered to the participants in the plan covered by this registration
statement, as required by Rule 428(b). Such documents are not being filed with
the Securities and Exchange Commission as part of this registration statement or
as prospectuses or prospectus supplements pursuant to Rule 424 of the Securities
Act.

                                       -1-
3
                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.          INCORPORATION OF DOCUMENTS BY REFERENCE

         The following documents filed by UBS AG (the "Company") are hereby
incorporated by reference in this registration statement:

         The Company's Annual Report on Form 20-F for the year ended December
31, 1999, filed pursuant to the Securities Exchange Act of 1934 (the "Exchange
Act"), as amended or supplemented by the prospectus filed by the Company
pursuant to Rule 424(b)(1) on October 3, 2000;

         The Company's reports on Form 6-K filed on May 25, 2000, July 12, 2000,
July 17, 2000, July 26, 2000, October 2, 2000, October 11, 2000 October 24, 2000
and October 27, 2000 filed pursuant to the Exchange Act;

         The description of the Company's Ordinary Shares, par value CHF 10 per
share, contained in the Company's registration statement on Form 20-F filed with
the Commission on May 9, 2000, pursuant to the Exchange Act (Registration No.
00115026) including any amendments or reports filed for the purposes of updating
such description; and

         All documents filed by the Company pursuant to Section 13(a) and 15(d)
of the Exchange Act of 1934, as amended, after the date of this registration
statement and prior to the filing of a post-effective amendment to this
registration statement which indicates that all securities offered hereby have
been sold or which deregisters all securities then remaining unsold, shall be
deemed to be incorporated by reference in this registration statement and to be
a part hereof from the filing date of such documents.

         Any statement contained in a document incorporated or deemed to be
incorporated by reference herein shall be deemed to be modified or superseded
for purposes of this registration statement to the extent that a statement
contained herein (or in any other subsequently filed document which also is
incorporated or deemed to be incorporated by reference herein) modifies or
supersedes such statement. Any such statement so modified or superseded shall
not be deemed, except as so modified or superseded, to constitute a part of this
registration statement.

ITEM 4.         DESCRIPTION OF SECURITIES

                Not applicable.

ITEM 5.         INTERESTS OF NAMED EXPERTS AND COUNSEL

                Not applicable.

                                       -2-
4
ITEM 6.         INDEMNIFICATION OF DIRECTORS AND OFFICERS

         Neither the UBS articles of association nor Swiss statutory law contain
provisions regarding the indemnification of directors and officers.

         According to general principles of Swiss employment law, an employer
may, under certain circumstances, be required to indemnify an employee against
losses and expenses incurred by him in the execution of his duties under the
employment agreement, unless the losses and expenses arise from the employee's
gross negligence or willful misconduct.

         UBS maintains directors' and officers' insurance for its directors and
officers.

ITEM 7.         EXEMPTION FROM REGISTRATION CLAIMED

                Not applicable.

ITEM 8.         EXHIBITS

Exhibit
  No.           Description

4.1             Articles of Association of UBS AG.

4.2             Organization Regulations of UBS AG.

5               Opinion of Baer & Karrer, Swiss counsel of UBS AG, regarding
                validity of the securities of UBS AG being registered under this
                Registration Statement.

23.1            Consent of Ernst & Young Ltd.

23.2            Consent of Baer & Karrer (Included in Exhibit 5 to this
                registration statement).

24              Power of Attorney.

ITEM 9.         UNDERTAKINGS

The undersigned registrant hereby undertakes:

(1) To file, during any period in which offers or sales are being made, a
post-effective amendment to this registration statement:

            (i)       To include any prospectus required by Section 10(a)(3) of
                      the Securities Act.

           (ii)       To reflect in the prospectus any facts or events arising
                      after the effective date of this registration statement
                      (or the most recent post-effective amendment thereof)
                      which, individually or in aggregate, represent a
                      fundamental change in the information set forth in this
                      registration statement. Notwithstanding the

                                       -3-
5
                      foregoing, any increase or decrease in volume of
                      securities offered (if the total dollar value of
                      securities offered would not exceed that which was
                      registered) and any deviation from the low or high end of
                      the estimated maximum offering range may be reflected in
                      the form of prospectus filed with the Commission pursuant
                      to Rule 424(b) if, in the aggregate, the changes in volume
                      and price represent no more than 20 percent change in the
                      maximum aggregate offering price set forth in the
                      "Calculation of Registration Fee" table in the effective
                      registration statement.

           (iii)      To include any material information with respect to the
                      plan of distribution not previously disclosed in this
                      registration statement or any material change to such
                      information in this registration statement;

                      provided, however, that paragraphs (a)(1)(i) and
                      (a)(1)(ii) of this Item 9 do not apply if the information
                      required to be included in the post-effective amendment by
                      those paragraphs is contained in periodic reports filed by
                      the Company pursuant to Section 13 or Section 15(d) of the
                      Exchange Act that are incorporated by reference in this
                      registration statement.

(2) That, for the purpose of determining any liability under the Securities Act,
each such post-effective amendment shall be deemed to be a new registration
statement relating to the securities offered therein, and the offering of such
securities at that time shall be deemed to be the initial bona fide offering
thereof.

(3) To remove from registration by means of a post-effective amendment any of
the securities being registered which remain unsold at the termination of the
offering.

(4) To file a post-effective amendment to the registration statement to include
any financial statements required by Item 8.A. of Form 20-F at the start of any
delayed offering or throughout a continuous offering. Financial statements and
information otherwise required by Section 10 (a) (3) of the Act need not be
furnished, provided, that the registrant includes in the prospectus, by means of
a post-effective amendment, financial statements required pursuant to this
paragraph (a) (4) and other information necessary to ensure that all other
information in the prospectus is at least as current as the date of those
financial statements. Notwithstanding the foregoing, with respect to
registration statements on Form F-3, a post-effective amendment need not be
filed to include financial statements and information required by Section 10(a)
(3) of the Act or Rule 3-19 of this chapter if such financial statements and
information are contained in periodic reports filed with or furnished to the
Commission by the registrant pursuant to Section 13, or Section 15 (d) of the
Securities Exchange Act of 1934, as amended, that are incorporated by reference
in the Form F-3.

(5) The undersigned Company hereby undertakes that, for purposes of determining
any liability under the Securities Act, each filing of the Company's annual
report pursuant to Section 13(a) or 15(d) of the Exchange Act (and, where
applicable, each filing of an employee benefit plan's annual report pursuant to
Section 15(d) of the Exchange Act) that is incorporated by reference in this
registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.

                                       -4-
6
(6) Insofar as indemnification for liabilities arising under the Securities Act
of 1933, as amended, may be permitted to directors, officers and controlling
persons of the Company pursuant to the foregoing provisions, or otherwise, the
Company has been advised that in the opinion of the Securities and Exchange
Commission such indemnification is against public policy as expressed in the Act
and is, therefore, unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the Company of expenses
incurred or paid by a director, officer or controlling person of the Company in
the successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Company will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Act and will be governed by the final adjudication of
such issue.

                                       -5-
7
                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, as amended,
the Company certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
registration statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Zurich, Switzerland, on November 3, 2000.

                           UBS AG

                           By: /s/ Luqman Arnold
                               -----------------------------------------
                           Name:  Luqman Arnold
                           Title: Chief Financial Officer

                           By: /s/ Robert B. Mills
                               -----------------------------------------
                           Name:  Robert B. Mills
                           Title: Managing Director

         Pursuant to the requirements of the Securities Act of 1933, as amended,
this registration statement has been signed by the following persons in the
indicated capacities on November 3, 2000.
Name                                      Title
----                                      -----
by:            *                          President and Group
      ---------------------------         Chief Executive Officer
Name: Marcel Ospel                        (Principal Executive Officer)

by:            *                          Chief Financial Officer
      ---------------------------         (Principal Financial Officer)
Name: Luqman Arnold

by:            *                          Group Controller
      ---------------------------         and Member of Group Managing Board
Name: Hugo Schaub                         (Principal Accounting Officer)

by:            *                          Chairman of the Board of Directors
      ---------------------------
Name: Alex Krauer

by:            *                          Vice Chairman of the Board of Directors
      ---------------------------
Name: Alberto Togni

by:            *                          Vice Chairman of the Board of Directors
      ---------------------------
Name: Markus Kundig
-6-
8
Name                                      Title
----                                      -----
by:               *                       Member of the Board of Directors
      ---------------------------
Name: Peter Bockli

by:               *                       Member of the Board of Directors
      ---------------------------
Name: Eric Honegger

by:               *                       Member of the Board of Directors
      ---------------------------
Name: Rolf A. Meyer

by:               *                       Member of the Board of Directors
      ---------------------------
Name: Hans Peter Ming

by:                                       Member of the Board of Directors
      ---------------------------
Name: Andreas Reinhart
*  By Power of Attorney

  /s/ Luqman Arnold
  -----------------------------------------
  Luqman Arnold

                                       -7-
9
         Pursuant to the requirements of Section 6(a) of the Securities Act of
1933, as amended, the Authorized Representative has duly caused this
Registration Statement to be signed on its behalf by the undersigned, solely in
its capacity as the duly authorized representative of UBS AG in the United
States, in The City of New York, State of New York, on the 3rd of November,
2000.

                                        By: /s/ Robert B. Mills
                                            -----------------------
                                        Name:  Robert B. Mills
                                        Title: Managing Director

                                       -8-
10
                                INDEX TO EXHIBITS

4.1            Articles of Association of UBS AG.

4.2            Organization Regulations of UBS AG.

5              Opinion of Baer & Karrer, Swiss counsel of UBS AG, regarding
               validity of the securities of UBS AG being registered under this
               Registration Statement.

23.1           Consent of Ernst & Young Ltd.

23.2           Consent of Baer & Karrer (Included in Exhibit 5 to this
               registration statement).

24             Power of Attorney.

                                       -9-