(Face of Security)

                                                                     EXHIBIT 4.2



THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A
NOMINEE THEREOF. THIS SECURITY MAY NOT BE EXCHANGED IN WHOLE OR IN PART FOR A
SECURITY REGISTERED, AND NO TRANSFER OF THIS SECURITY IN WHOLE OR IN PART MAY BE
REGISTERED, IN THE NAME OF ANY PERSON OTHER THAN SUCH DEPOSITARY OR A NOMINEE
THEREOF, EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE INDENTURE.

UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO UBS AG, OR ITS
AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE
ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO
CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

BY PURCHASING THIS SECURITY, THE HOLDER AGREES TO CHARACTERIZE THIS SECURITY FOR
ALL U.S. FEDERAL INCOME TAX PURPOSES AS PROVIDED IN SECTION 5 ON THE FACE OF
THIS SECURITY.


<PAGE>


CUSIP NO. 90261KANO

                                     UBS AG

                           MEDIUM-TERM NOTES, SERIES A

                               -------------------

                CONTINGENT RATE FORENS(SM) DUE JANUARY 22, 2002
          (Principal Protected U.S. Dollar Denominated One-Touch FORENS
             Linked to Japanese Yen/U.S. Dollar Spot Exchange Rate)

                               -------------------


         The following terms apply to this Security. Capitalized terms that are
not defined the first time they are used in this Security shall have the
meanings indicated elsewhere in this Security.

FACE AMOUNT:  $1,000

PRINCIPAL AMOUNT: on the Maturity Date, the Company shall redeem this Security
for 100% of the Face Amount hereof in U.S. dollars.

CALCULATION AGENT:  UBS Warburg LLC.

DEFEASANCE: neither full defeasance nor covenant defeasance applies to this
Security.

CONTINGENT COUPON: 9.0% per annum if the Calculation Agent determines that a
spot foreign exchange transaction of at least $3 million trades in the interbank
foreign exchange market at a Japanese yen/U.S. dollar spot exchange rate equal
to or greater than 138.0 Japanese yen per U.S. dollar during the period between
4:00 p.m., New York City time, on July 12, 2001 and 10:00 a.m., New York City
time, on January 15, 2002. If no Trigger Event occurs, the FORENS will not bear
any interest.

TRADE DATE:  July 12, 2001

SETTLEMENT DATE:  July 19, 2001

FINAL DETERMINATION DATE: January 15, 2002

STATED MATURITY DATE:  January 22, 2002

LISTING:  American Stock Exchange.

BOOKING BRANCH:  UBS AG, Jersey Branch



                    (Face of Security continued on next page)

                                       -2-


<PAGE>


                               (Face of Security)

OTHER TERMS:

         All terms used in this Security that are not defined in this Security
but are defined in the Indenture referred to on the reverse of this Security
shall have the meanings assigned to them in the Indenture. Section headings on
the face of this Security are for convenience only and shall not affect the
construction of this Security.

         "Business Day" means any day that is not a Saturday, a Sunday or a day
on which the banking institutions in The City of New York, generally, are
authorized or obligated by law, regulation or executive order to close and that
is also a day on which commercial banks and foreign exchange markets settle
payments in U.S. dollars in The City of New York.

         "Contingent Coupon" means the contingent coupon of 9.0% payable if, but
only if, a Trigger Event (as defined below) occurs.

                   "Default Amount" means, on any day, an amount in U.S. dollars
equal to the sum of (i) the principal amount of the Security and (ii) the cost
of having a Qualified Financial Institution expressly assume the Company's
contingent obligation in respect of the due and punctual payment of the
Contingent Coupon with respect to the Security as of that day as if no default
or acceleration had occurred, or undertake the Company's contingent obligations
in respect of the due and punctual payment of the Contingent Coupon on the same
economic terms as are provided for by the Security. Such cost will equal the
lowest amount that a Qualified Financial Institution (selected as provided
below) would charge to effect such assumption or undertaking. During the Default
Quotation Period, each of the Holder of the Securities and the Company may
request a Qualified Financial Institution to provide a quotation of the amount
it would charge to effect such assumption or undertaking and notify the other in
writing of such quotation. The amount referred to in clause (ii) above will
equal the lowest (or, if there is only one, the only) quotation so obtained, and
as to which notice is so given, during the Default Quotation Period; provided
that, with respect to any quotation, the party not obtaining such quotation may
object, on reasonable and significant grounds, to the effectuation of such
assumption or undertaking by the Qualified Financial Institution providing such
quotation and notify the other party in writing of such grounds within two
Business Days after the last day of the Default Quotation Period, in which case
such quotation will be disregarded in determining the Default Amount. The
"Default Quotation Period" will be the period beginning on the day the Default
Amount first becomes due and ending on the third Business Day after such due
day, unless no such quotation is so obtained, or unless every such quotation so
obtained is objected to within five Business Days after such due day as provided
above, in which case the Default Quotation Period will


                    (Face of Security continued on next page)

                                       -3-


<PAGE>


                               (Face of Security)

continue until the third Business Day after the first Business Day on which
prompt notice is given of such a quotation as provided above, unless such
quotation is objected to as provided above within five Business Days after such
first Business Day, in which case the Default Quotation Period will continue as
provided in this sentence. Notwithstanding the foregoing, in no event shall the
default quotation period extend beyond the Final Determination Date.

         "Final Determination Date" means January 15, 2002.

         "Qualified Financial Institution" means, at any time, a financial
institution organized under the laws of any jurisdiction in the United States of
America, Europe or Japan that at such time has outstanding debt obligations with
a stated maturity of one year or less from the date of issue and rated A-1 or
higher by Standard & Poor's Ratings Group or any successor, or P-1 or higher by
Moody's Investors Service, Inc. or any successor, or, in either case, such other
comparable rating, if any, then used by such rating agency.

         "Settlement Date" means July 19, 2001.

         "Stated Maturity Date" means January 22, 2002 or, if such day is not a
Business Day, the next succeeding Business Day.

         "Trade Date" means July 12, 2001.

         "Trigger Event" means that the Calculation Agent determines that one or
more consecutive spot foreign exchange transactions amounting to at least $3
million have traded in the interbank foreign exchange market through the
Electronic Broking System or Reuters 2002 systems, or have been traded by the
Company or one of its affiliates in the interbank foreign exchange market, at a
Japanese yen/U.S. dollar spot exchange rate equal to or greater than 138.0
Japanese yen per U.S. dollar, during the period between 4:00 p.m., New York City
time, on July 12, 2001 and 10:00 a.m., New York City time, on January 15, 2002.
The Calculation Agent will not review any other source of information in the
interbank foreign exchange market for Japanese yen/U.S. dollar spot
transactions, and no other transactions or information on exchange rates will
have any effect on whether a Trigger Event has occurred. The Calculation Agent
will observe only those transactions that occur during the hours between 5:00
a.m. Sydney time on any Monday and 5:00 p.m. New York City time on any Friday
during that period. The Calculation Agent will count as a single transaction (i)
two or more transactions if they are executed consecutively within the same
dealing system; and (ii) two or more transactions if they are traded
consecutively by UBS or one of its affiliates in the interbank foreign exchange
market, and together relate to an aggregate amount of at least $3 million.


                    (Face of Security continued on next page)

                                       -4-


<PAGE>


                               (Face of Security)

                             -----------------------

         1. Promise to Pay Principal and Interest
            -------------------------------------

         UBS AG, a corporation duly organized and existing under the laws of
Switzerland (herein called the "Company", which term includes any successor
Person under the Indenture hereinafter referred to), for value received, hereby
promises to pay, or cause to be paid, to Cede & Co., as nominee for The
Depository Trust Company, on the Stated Maturity Date, 100% of the Outstanding
Face Amount as provided under "Principal Amount" and if the Calculation Agent
determines that a Trigger Event has occurred, to pay, or cause to be paid,
interest on the Outstanding Face Amount, from and including July 19, 2001 to but
excluding the Stated Maturity Date, at the rate of 9.0% per year. If no such
Trigger Event occurs, the Security will not bear any interest.

         2. Payment of Interest
            -------------------

         If a Trigger Event occurs and interest becomes payable, then the
interest so payable will be paid in U.S. dollars to the Person to whom the
Principal Amount is payable.

         3. Principal Amount
            ----------------

         The principal of this Security that becomes due and payable on the
Stated Maturity Date shall be equal to the Face Amount hereof. The principal of
this Security that becomes due and payable upon acceleration of the Maturity
hereof after an Event of Default has occurred pursuant to the Indenture shall be
the Default Amount. When payment has been made, or such payment has been made
available, as provided herein, the principal of this Security shall be deemed to
have been paid in full, whether or not this Security shall have been surrendered
for payment or cancellation.

         4. Role of Calculation Agent
            -------------------------

         The Calculation Agent will be solely responsible for (x) the
determination of whether a Trigger Event has occurred, (y) all determinations
and calculations regarding the Default Amount, and (z) all such other matters as
may be specified elsewhere herein as matters to be determined by the Calculation
Agent. The Calculation Agent shall make all such determinations and calculations
in its sole discretion (and, in the case of any determination as to whether a
Trigger Event has occurred, in good faith and in a commercially reasonable
manner), and absent manifest error all determinations and calculations made by
the Calculation Agent shall be final and binding on the Company, the


                    (Face of Security continued on next page)

                                       -5-


<PAGE>


                               (Face of Security)

Holder and all other Persons having an interest in this Security, without
liability on the part of the Calculation Agent.

         The Company shall take such action as shall be necessary to ensure that
there is at all relevant times a financial institution serving as the
Calculation Agent hereunder. The Company may, in its sole discretion at any time
and from time to time, upon written notice to the Trustee, but without notice to
the Holder of this Security, terminate the appointment of any Person serving as
the Calculation Agent and appoint another Person (including any Affiliate of the
Company) to serve as such agent. Insofar as this Security provides for the
Calculation Agent to obtain prices or other information from any institution or
other source, the Calculation Agent may do so from any source or sources of the
kind contemplated or otherwise permitted hereby notwithstanding that any one or
more of such sources are such agent, Affiliates of such agent or Affiliates of
the Company.

         5. Tax Characterization
            --------------------

         By its purchase of this Security, the Holder, on behalf of itself and
any other Person having a beneficial interest in this Security, hereby agrees
with the Company (in the absence of an administrative determination or judicial
ruling to the contrary) that each of the Holder and the Company will
characterize this Security for all U.S. federal income tax purposes as (i) a
debt instrument that is not subject to Section 988 of the Internal Revenue Code
and (ii) as not having accrued any portion of the Contingent Coupon prior to the
occurrence of a Trigger Event and as accruing the Contingent Coupon notably over
the entire term of the Security (including for the period prior to the
occurrence of a Trigger Event once a Trigger Event occurs).

         6. Payment and Delivery
            --------------------

         Payment of any amount payable on this Security in cash will be made in
such coin or currency of the United States of America as at the time of payment
is legal tender for payment of public and private debts. Payment will be made to
an account designated by the Holder (in writing to the Company and the Trustee
on or before the Final Determination Date) and acceptable to the Company or, if
no such account is designated and acceptable as aforesaid, at the office or
agency of the Company maintained for that purpose in The City of New York;
provided, however, that, at the option of the Company, payment of interest may


                    (Face of Security continued on next page)

                                       -6-


<PAGE>


                               (Face of Security)


be made by check mailed to the address of the Person entitled thereto as such
address shall appear in the Security Register; and provided further, however,
that payment or delivery at Maturity shall be made only upon surrender of this
Security at such office or agency (unless the Company waives surrender).
Notwithstanding the foregoing, if this Security is a Global Security, any
payment or delivery may be made pursuant to the Applicable Procedures of the
Depositary as permitted in said Indenture. In lieu of making any delivery of
property it is obligated hereunder to make, the Company shall be entitled to
cause such delivery to be made on its behalf, provided such delivery is
otherwise made as provided herein.

         7. Holidays
            --------

         Notwithstanding any provision of this Security or of the Indenture, if
any delivery or payment of principal or interest would otherwise be due on this
Security on a day (the "Specified Day") that is not a Business Day, such
delivery or payment may be made (or such principal or interest may be made
available for delivery or payment) on the next succeeding Business Day with the
same force and effect as if such delivery or payment were made on the Specified
Day. The provisions of this Section shall apply to this Security in lieu of the
provisions of Section 114 of the Indenture.

         8. Reverse of this Security
            ------------------------

         Reference is hereby made to the further provisions of this Security set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

         9. Certificate of Authentication
            -----------------------------

         Unless the certificate of authentication hereon has been executed by
the Trustee referred to on the reverse hereof by manual signature, this Security
shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.


                    (Face of Security continued on next page)

                                       -7-


<PAGE>


                               (Face of Security)

         IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed.



                                      UBS AG

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


                                      By
                                         -------------------------------
                                         Name:  Robert C. Dinerstein
                                         Title: Managing Director


         This is one of the Securities of the series designated herein and
referred to in the Indenture.

Dated:


                                      U.S. BANK TRUST NATIONAL ASSOCIATION,
                                      AS TRUSTEE


                                      By
                                         ------------------------------------
                                               Authorized Signatory


<PAGE>


                              (Reverse of Security)

         This Security is one of a duly authorized issue of securities of the
Company (herein called the "Securities") issued and to be issued in one or more
series under an Indenture, dated as of November 21, 2000 (herein called the
"Indenture", which term shall have the meaning assigned to it in such
instrument), between the Company and U.S. Bank Trust National Association, as
Trustee (herein called the "Trustee", which term includes any successor trustee
under the Indenture), and reference is hereby made to the Indenture for a
statement of the respective rights, limitations of rights, duties and immunities
thereunder of the Company, the Trustee, the Holders of the Securities and of the
terms upon which the Securities are, and are to be, authenticated and delivered.
Insofar as the provisions of the Indenture may conflict with the provisions set
forth on the face of this Security, the latter shall control for purposes of
this Security.

         This Security is one of the series designated on the face hereof,
limited to an aggregate initial offering price not to exceed $25,000,000 (or the
equivalent thereof in any other currency or currencies or currency units), which
amount may be increased at the option of the Company if in the future it
determines that it may wish to sell additional Securities of this series.
References herein to "this series" mean the series designated on the face
hereof.

         Payments under the Securities will be made without withholding or
deduction for or on account of any present or future tax, duty, assessment or
governmental charge imposed upon or as a result of such payments by Switzerland
or any jurisdiction in which a branch of the Company through which the
Securities are issued is located (or any political subdivision or taxing
authority thereof or therein) (a "Relevant Jurisdiction"), ("Taxes"), unless
required by law. To the extent any such Taxes are so levied or imposed, the
Company will, subject to the exceptions and limitations set forth in Section
1007 of the Indenture, pay such additional amounts ("Additional Amounts") to the
Holder of any Security who is not a resident of the Relevant Jurisdiction as may
be necessary in order that every net payment of the principal of and interest on
such Security and any other amounts payable on such Security, after withholding
for or on account of such Taxes imposed upon or as a result of such payment,
will not be less than the amount provided for in such Security to be then due
and payable.

         If at any time as a result of any change in or amendment to the laws or
regulations of a Relevant Jurisdiction affecting taxation, or a change in any
application or interpretation of such laws or regulations (including the
decision of any court or tribunal) either generally or in relation to any
particular Securities, which change, amendment, application or interpretation
becomes effective on or after the Trade Date in making any payment of, or in
respect of, the principal amount of, or any premium or interest on, the
Securities, the Company would be required to pay any Additional Amounts with
respect thereto, then the Securities will be redeemable upon not less than 10
nor more than 60 days' notice by mail, at any time thereafter, in whole but not
in part, at the election of the


                  (Reverse of Security continued on next page)

                                       -9-


<PAGE>


                              (Reverse of Security)

Company as provided in the Indenture at their principal amount, together in the
case of any such redemption with any accrued but unpaid interest to, the
Redemption Date.

         The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Company and the rights of the Holders of the Securities of each series to be
affected under the Indenture at any time by the Company and the Trustee with the
consent of the Holders of a majority in principal amount of the Securities at
the time Outstanding of all series to be affected (considered together as one
class for this purpose). The Indenture also contains provisions (i) permitting
the Holders of a majority in principal amount of the Securities at the time
Outstanding of all series to be affected under the Indenture (considered
together as one class for this purpose), on behalf of the Holders of all
Securities of such series, to waive compliance by the Company with certain
provisions of the Indenture and (ii) permitting the Holders of a majority in
principal amount of the Securities at the time Outstanding of any series to be
affected under the Indenture (with each such series considered separately for
this purpose), on behalf of the Holders of all Securities of such series, to
waive certain past defaults under the Indenture and their consequences. Any such
consent or waiver by the Holder of this Security shall be conclusive and binding
upon such Holder and upon all future Holders of this Security and of any
Security issued upon the registration of transfer hereof or in exchange herefor
or in lieu hereof, whether or not notation of such consent or waiver is made
upon this Security.

         As provided in and subject to the provisions of the Indenture, the
Holder of this Security shall not have the right to institute any proceeding
with respect to the Indenture or for the appointment of a receiver or trustee or
for any other remedy thereunder, unless such Holder shall have previously given
the Trustee written notice of a continuing Event of Default with respect to the
Securities of this series, the Holders of not less than 25% in principal amount
of the Securities of this series at the time Outstanding shall have made written
request to the Trustee to institute proceedings in respect of such Event of
Default as Trustee and offered the Trustee indemnity reasonably satisfactory to
it, and the Trustee shall not have received from the Holders of a majority in
principal amount of Securities of this series at the time Outstanding a
direction inconsistent with such request, and shall have failed to institute any
such proceeding, for 60 days after receipt of such notice, request and offer of
indemnity. The foregoing shall not apply to any suit instituted by the Holder of
this Security for the enforcement of any payment of principal hereof or any
interest hereon on or after the respective due dates expressed herein.

         No reference herein to the Indenture and no provision of this Security
or of the Indenture shall alter or impair the obligation of the Company, which
is absolute and unconditional, to pay the principal of and, if a Trigger Event
has occurred, the interest on this Security as herein provided.


                  (Reverse of Security continued on next page)

                                      -10-


<PAGE>


                              (Reverse of Security)

         As provided in the Indenture and subject to certain limitations therein
set forth, the transfer of this Security is registrable in the Security
Register, upon surrender of this Security for registration of transfer at the
office or agency of the Company in any place where the principal of and interest
on this Security are payable, duly endorsed by, or accompanied by a written
instrument of transfer in form satisfactory to the Company and the Security
Registrar duly executed by, the Holder hereof or such Holder's attorney duly
authorized in writing. Thereupon one or more new Securities of this series and
of like tenor, of authorized denominations and for the same aggregate Face
Amount, will be issued to the designated transferee or transferees.

         This Security, and any other Securities of this series and of like
tenor, are issuable only in registered form without coupons in denominations of
any multiple of $1,000. As provided in the Indenture and subject to certain
limitations therein set forth, Securities of this series are exchangeable for a
like aggregate principal amount of Securities of this series and of like tenor
of a different authorized denomination, as requested by the Holder surrendering
the same.

         No service charge shall be made for any such registration of transfer
or exchange, but the Company may require payment of a sum sufficient to cover
any tax or other governmental charge payable in connection therewith.

         Prior to due presentment of this Security for registration of transfer,
the Company, the Trustee and any agent of the Company or the Trustee may treat
the Person in whose name this Security is registered as the owner hereof for all
purposes, whether or not this Security be overdue, and neither the Company, the
Trustee nor any such agent shall be affected by notice to the contrary.

         THIS SECURITY AND THE INDENTURE SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.


                                      -11-