(Face of Security)

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.



<PAGE>

CUSIP NO. o


                                     UBS AG

                           MEDIUM-TERM NOTES, SERIES A
                                 --------------

                     VARIABLE RATE CREDIT LINKED NOTES DUE o
                           (Linked to the credit of o)
                                 --------------

         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.

PRINCIPAL AMOUNT:  $o

REFERENCE ENTITY:  o

STATED MATURITY DATE:  o

ORIGINAL ISSUE DATE:  o

INTEREST RATE:  1-month LIBOR plus o% per annum

INITIAL INTEREST RATE:  o% (including spread)

INTEREST PAYMENT DATES:  The o of each month, commencing o.

INTEREST DETERMINATION DATES: Second London Business Day preceding the Interest
Reset Date.

BOOKING BRANCH:  Jersey Branch

INTEREST RESET DATES:  The o day of each month, commencing o.

REGULAR RECORD DATE: Fifteenth calendar date next preceding the Interest Payment
Date.

POSTPONEMENT OF STATED MATURITY DATE: If this Security is subject to early
redemption due to a Credit Event with respect to the Reference Entity, the
Stated Maturity Date will be postponed, if necessary, to permit the Calculation
Agent to calculate the Redemption Price, as provided in Section 7. The Stated
Maturity Date will not be postponed beyond o.

SPECIFIED CURRENCY:  Principal and interest payments in U.S. Dollars only.

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

CALCULATION AGENT:  UBS Warburg LLC

                    (Face of Security continued on next page)

                                        2

<PAGE>

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.

         "Bankruptcy" means that the Reference Entity (a) is dissolved (other
than pursuant to a consolidation, amalgamation or merger); (b) suffers an
insolvency or inability or failure to pay its debts as they become due; (c) has
a general assignment, arrangement or composition with or for the benefit of its
creditors; (d) is instituting or has instituted against it a proceeding seeking
a judgment of insolvency or bankruptcy or any other relief under any bankruptcy
or insolvency law or other similar law affecting creditors' rights, or a
petition is presented for its winding-up or liquidation, and, in the case of any
such proceeding or petition instituted or presented against it, such proceeding
or petition either (i) results in a judgment of insolvency or bankruptcy or the
entry of an order for relief or the making of an order for its winding-up or
liquidation or (ii) is not dismissed, discharged, stayed or restrained in each
case within 30 days of the institution or presentation thereof; (e) has a
resolution passed for its winding-up, official management or liquidation (other
than pursuant to a consolidation, amalgamation or merger); (f) seeks or becomes
subject to the appointment of an administrator, provisional liquidator,
conservator, receiver, trustee, custodian or other similar official for it or
for all or substantially all its assets; (g) has a secured party take possession
of all or substantially all its assets or has a distress, execution, attachment,
sequestration or other legal process levied, enforced or sued on or against all
or substantially all its assets and such secured party maintains possession, or
any such process is not dismissed, discharged, stayed or restrained, in each
case within 30 days thereafter; (h) causes or becomes subject to any event with
respect to it which, under the applicable laws of any jurisdiction, has an
analogous effect to any of the events specified above.

         "Business Day" means any day that is not a Saturday, a Sunday or a day
on which banking institutions in The City of New York generally are authorized
or obligated by law, regulation or executive order to close and is also a London
Business Day.

         "Credit Event" means (a) a Bankruptcy, (b) an Obligation Acceleration,
(c) a Failure to Pay, or (d) a Restructuring.

         "Failure to Pay" means, after the expiration of any applicable grace
period, the Reference Entity fails to pay when and where due required payments
of at least $1 million (or an equivalent amount in another currency) on one or
more of its Obligations, whether in the aggregate or individually.

         "Interest Period" means the period commencing on and including each
Interest Payment Date and ending on and including the day preceding the next
Interest Payment Date, with the exception that the first Interest Period shall
commence on and include o.

                    (Face of Security continued on next page)

                                        3

<PAGE>

         "London Business Day" means any day on which dealings in U.S. dollars
are transacted in the London interbank market.

         "Multiple Holder Obligation" means an Obligation that (i) at the time
the Calculation Agent determines that a Credit Event has occurred, is held by
more than three unaffiliated holders and (ii) with respect to which a percentage
of holders (determined pursuant to the terms of the Obligation) at least equal
to 66 2/3% is required to consent to the event which would otherwise constitute
a Restructuring Event.

         "Obligation" means obligations in the form of a bond, note,
certificated debt security or other debt security or documented by a term loan
agreement, revolving loan agreement or other similar credit agreement, of the
Reference Entity itself or another entity that are guaranteed by the Reference
Entity.

         "Obligation Acceleration" means one or more Obligations are accelerated
due to an event of default or similar event, other than a failure to make any
required payment under one or more Obligations; provided, however, (a) the
relevant Obligation(s) must have a face amount of at least $10 million (or an
equivalent amount in another currency), and (b) the Obligation must not be
repaid, and the default, event of default or similar event, must continue to
exist, for at least a period of time equal to the greater of (i) 60 days and
(ii) the number of days ending on the next payment date with respect to the
relevant obligation.

         "Publicly Available Information" means (a) information that reasonably
confirms any of the facts relevant to the determination that a Credit Event has
occurred and which (i) has been published in or on not less than two
internationally recognized published or electronically displayed news sources
(for example, Bloomberg Service, Dow Jones Telerate Service, Reuter Monitor
Money Rates Services, Dow Jones News Wire, Wall Street Journal, New York Times,
Financial Times and Nihon Keizai Shinbun), except that, if the Company or any of
its affiliates is cited as the sole source of such information, then such
information will not be considered Publicly Available Information unless the
Company or its affiliate, as applicable, is acting in the capacity of a trustee,
fiscal agent, administrative agent, clearing agent or paying agent for an
Obligation of the Reference Entity; (ii) is information received in writing from
(A) the Reference Entity so long as the Reference Entity is not the sole holder
of this Security or (B) a trustee, fiscal agent, administrative agent, clearing
agent or paying agent for an Obligation of the Reference Entity; (iii) is
information contained in any petition or filing instituting a bankruptcy,
insolvency, winding-up or liquidation proceeding against or by the Reference
Entity; or (iv) is information contained in any order, decree or notice, however
described, of a court, tribunal, regulatory authority or similar administrative
or judicial body. The Publicly Available Information need not state that the
occurrence of a particular event with respect to the Reference Entity meets one
or more of the elements of a Credit Event.

         "Restructuring" means the Reference Entity, or a government authority
or a private entity charged with regulation of financial markets, agrees to or
announces a binding change to one or more Obligations (which, for purposes of
this paragraph only,

                    (Face of Security continued on next page)

                                        4

<PAGE>

must be a Multiple Holder Obligation) with an aggregate face amount of at least
$10 million (or an equivalent amount in another currency) that affects the
timing or amount of interest payable on the Obligation, reduces the principal or
premium payable on the Obligation at maturity or at scheduled redemption dates
or changes the timing of such payments (a "Restructuring Event"); provided,
however, that such a change will be a Credit Event only if it is not (i)
provided for under the terms of the Obligation or (ii) due to an administrative
adjustment; and provided, further, that the change must result directly or
indirectly from a deterioration in the creditworthiness or financial condition
of the Reference Entity.

         "Stated Maturity Date" means o.

         "Trade Date" means o.

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



         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, or registered assigns, the Principal Amount on the
Stated Maturity Date and to pay interest thereon from the Original Issue Date,
or from the most recent date to which interest has been paid or duly provided
for, monthly in arrears on the fifth day of each month (an "Interest Payment
Date") and on the Stated Maturity Date, commencing o, at the per annum rate of
1-month LIBOR (as defined below), as determined by the Calculation Agent, plus a
spread of o%, until the principal of this Security is paid or made available for
payment; provided, however, that if this Security is subject to early redemption
due to a Credit Event with respect to the Reference Entity prior to the Stated
Maturity Date, interest shall cease to accrue from and including the Credit
Event Determination Date (as defined below) and the Company shall thereafter be
obligated to pay only the Redemption Price (together with any accrued but unpaid
interest to but excluding the Credit Event Determination Date) on the Redemption
Date. Any installment of interest hereunder that is overdue at any time shall
also bear interest (to the extent that payment of such interest shall be legally
enforceable) at the rate per annum at which the principal then bears interest,
from the date any such amount first become overdue until it is paid or made
available for payment. Notwithstanding the foregoing, interest on any principal
or installment of interest that is overdue shall be payable on demand.

         2. Payment of Interest

         The interest so payable, and punctually paid or made available for
payment, on any Interest Payment Date will, as provided in the Indenture, be
paid to

                    (Face of Security continued on next page)

                                        5

<PAGE>

the Person in whose name this Security (or one or more Predecessor Securities)
is registered at the close of business on the Regular Record Date for such
Interest Payment Date, which shall be the fifteenth calendar day (whether or not
a Business Day) next preceding such Interest Payment Date. Any interest so
payable, but not punctually paid or made available for payment, on any Interest
Payment Date will forthwith cease to be payable to the Holder on such Regular
Record Date and such Defaulted Interest may either be paid to the Person in
whose name this Security (or one or more Predecessor Securities) is registered
at the close of business on a Special Record Date for the payment of such
Defaulted Interest to be fixed by the Trustee, notice whereof shall be given to
the Holder of this Security not less than 10 days prior to such Special Record
Date, or be paid in any other lawful manner not inconsistent with the
requirements of any securities exchange on which this Security may be listed,
and upon such notice as may be required by such exchange, all as more fully
provided in the Indenture.

         3. Determination of Interest Rate
            ------------------------------

         The Calculation Agent will determine on each Interest Determination
Date the interest rate that takes effect on the related Interest Reset Date in
accordance with the following provisions.

         The per annum rate of interest for each Interest Period will be 1-month
LIBOR on the Interest Determination Date relating to the Interest Reset Date
immediately preceding the first day of such Interest Period plus a spread of o%.
The base rate (the "Initial Base Rate") for the first Interest Period shall be
o%. "1-month LIBOR" for each subsequent Interest Period will be determined by
the Calculation Agent in accordance with the following provisions:

         (a) On each Interest Determination Date, the Calculation Agent will
ascertain the offered rate appearing on the Telerate LIBOR Page (as defined
below), as of 11:00 A.M., London time, on such Interest Determination Date for
deposits of U.S. dollars for a period of one month beginning on the relevant
Interest Reset Date.

         (b) If such rate does not appear on the Telerate LIBOR Page, then
1-month LIBOR will be determined on the basis of the rates, at approximately
11:00 A.M., London time, on such Interest Determination Date, at which deposits
of the following kind are offered to prime banks in the London interbank market
by four major banks in that market selected by the Calculation Agent: deposits
of U.S. dollars for a period of one month beginning on the relevant Interest
Reset Date and in a Representative Amount (as defined below). The Calculation
Agent will request the principal London office of each such bank to provide a
quotation of its rate. If at least two quotations are provided, 1-month LIBOR
for such Interest Determination Date will be the arithmetic mean of the
quotations.

         (c) If fewer than two quotations are provided as described in clause
(b) above, 1-month LIBOR for such Interest Determination Date will be the
arithmetic mean of the rates for loans of the following kind to leading European
banks quoted, at approximately 11:00 A.M. in The City of New York, on such
Interest Determination

                    (Face of Security continued on next page)

                                        6


<PAGE>

Date, by three major banks in The City of New York selected by the Calculation
Agent: loans of U.S. dollars for a period of one month beginning on the relevant
Interest Reset Date and in a Representative Amount.

         (d) If fewer than three banks selected by the Calculation Agent are
quoting as described in clause (c) above, 1-month LIBOR will be 1-month LIBOR in
effect on such Interest Determination Date (or, in the case of the first
Interest Reset Date, the Initial Base Rate).

         "Representative Amount" means an amount that, in the Calculation
Agent's judgment, is representative of a single transaction in the relevant
market at the relevant time.

         "Telerate LIBOR Page" means Telerate Page 3750 or any replacement page
or pages on which London interbank rates of major banks for U.S. dollars are
displayed.

         "Telerate Page" means the display of Bridge Telerate, Inc., or any
successor service, on the page or pages specified in the definition of Telerate
Libor Page, or any replacement page or pages on that service.

         Notwithstanding the foregoing, the rate of interest that accrues on
this Security shall not at any time be higher than the maximum rate permitted by
New York law, as the same may be modified by United States law of general
application.

         4. Calculation of Interest
            -----------------------

         Payments of interest hereon with respect to any Interest Payment Date
or at the Stated Maturity Date of the principal hereof will include interest
accrued to but excluding such Interest Payment Date or such Stated Maturity
Date, as the case may be. Accrued interest from the Original Issue Date or from
the last date to which interest has been paid or duly provided for shall be
calculated by the Calculation Agent by multiplying the Principal Amount by an
accrued interest factor. Such accrued interest factor shall be computed by
adding the interest factors calculated for each day from and including the
Original Issue Date or from and including the last date to which interest has
been paid or duly provided for, to but excluding the date for which accrued
interest is being calculated. The interest factor for each such day shall be
expressed as a decimal and computed by dividing the interest rate (also
expressed as a decimal) in effect on such day by 360.

         5. Principal Amount
            ----------------

         The principal of this Security that becomes due and payable on the
Stated Maturity Date shall be the Principal 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
Principal Amount unless a Credit Event Determination Date has occurred prior to
the date of acceleration in which

                    (Face of Security continued on next page)

                                        7

<PAGE>

event only the Redemption Price (together with any accrued but unpaid interest
to the Credit Event Determination Date) shall be due and payable on the date to
which the maturity hereof is accelerated. When the cash referred to in either of
the two preceding sentences has been paid as provided herein (or such payment
has been made available), 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.

         6. Redemption
            ----------

         If, in the opinion of the Calculation Agent, one or more Credit Events
has occurred with respect to the Reference Entity, the Company may, at its
option, upon not less than five Business Days' notice of redemption to the
Holder of this Security, redeem this Security by paying the Redemption Price
calculated as described below. Any such notice of redemption shall describe the
Credit Event in reasonable detail and cite Publicly Available Information
confirming the occurrence of such Credit Event, specify the Redemption Date and
state the Redemption Price. The Redemption Price, if any, will be paid as soon
as practicable and no later than ten days after delivery of the notice of
redemption. The date as of which the Calculation Agent determines that a Credit
Event has occurred is referred to herein as the "Credit Event Determination
Date."

         The Calculation Agent shall determine the Redemption Price in the
following manner: thirty calendar days after the Credit Event Determination
Date, the Calculation Agent will for a period of three consecutive Business Days
(commencing as of the thirty-first day or the first succeeding Business Day if
such thirty-first day is not a Business Day) ask at least three dealers in
Obligations of the Reference Entity to give their firm bids for the cash value
of selected Obligations of the Reference Entity. The face amount of these
Obligations must equal the Principal Amount of this Security. For this purpose,
the Calculation Agent will select, in its sole discretion, one or more
Obligations of the Reference Entity for valuation. The specific Obligations
selected by the Calculation Agent are referred to as "Valuation Obligations" and
they must: (a) rank at least equal in priority of payment with other senior
unsecured obligations of the Reference Entity; (b) be payable only in U.S.
Dollars; (c) not be repayable in an amount determined by reference to any
formula or subject to any contingency; (d) bear interest at either a fixed or
floating rate that is paid on a periodic basis and computed on a benchmark
interest rate plus or minus a spread, if any; (e) with regard to any Credit
Event other than a Restructuring Event, be transferable to institutional
investors without any contractual, statutory or regulatory restriction (other
than resale restrictions such as pursuant to Rule 144A or Regulation S under the
Securities Act of 1933, as amended); (f) with regard to a Credit Event that is a
Restructuring Event, be transferable or capable of being assigned or novated to
one or more eligible transferees (e.g., a bank, insurance company, mutual fund
or a corporation) without the consent of any party being required; (g) with
regard to any Credit Event other than a Restructuring Event, have a remaining
maturity from the Credit Event Determination Date of no greater than forty-four
months; and (h) with regard to a Restructuring Event, have a remaining maturity
not later than the date that is the earlier of thirty months following the date
of the Restructuring Event and the final maturity date of the restructured
obligation, but in any event no earlier than the

                    (Face of Security continued on next page)

                                        8

<PAGE>

Stated Maturity Date of this Security and no later than thirty months after the
Stated Maturity Date of this Security.

         If there is more than one Obligation of the Reference Entity that
satisfies the above criteria, the Calculation Agent may select one or more of
such Obligations for valuation.

         On each of the three Business Days on which the calculation agent is
required to seek bids on the Obligations of the Reference Entity, the
Calculation Agent will seek quotations for the cash value of the Valuation
Obligations at 11:00 A.M. New York City time. If on any such day more than three
quotations are received, then the Redemption Price will be the arithmetic
average of the quotations, ignoring the highest and lowest of such quotations.
If on any such day exactly three quotations are received, the Redemption Price
will be the quotation remaining after disregarding the highest and lowest
quotations. If after seeking quotations on the third such day there are fewer
than three quotations received, then the Calculation Agent will wait eighteen
days and request quotations (commencing as of the nineteenth day or the first
succeeding Business Day if such nineteenth day is not a Business Day) from
dealers who were not previously asked to provide quotations (to the extent
practicable) for a period of three consecutive calendar days. If the Calculation
Agent once again receives fewer than three quotations on all three of those days
then the Calculation Agent, acting in a commercially reasonable manner, will
determine the Redemption Price by making a good faith estimate of the value of
the Valuation Obligations, including using the weighted average of any firm
quotations obtained in accordance with the above provisions, each for an amount
of Obligations with a face amount of as large a size as available but less than
the Principal Amount (but in any event not to be less than $1,000,000).
Notwithstanding the above, the Calculation Agent is required to consider any
firm bid offered by a reputable buyer that stands ready and able to execute a
transaction at the quoted price that it is aware of. The Calculation Agent may
determine that the Redemption Price is zero.

         7. Postponement of Stated Maturity Date
         ---------------------------------------

         If this Security is subject to early redemption due to a Credit Event,
the maturity of this Security will be postponed, if necessary, to permit the
Calculation Agent the number of days (as described in Section 6 above) from the
Credit Event Determination Date to calculate and pay the Redemption Price;
provided, however, that in no event will the Stated Maturity Date be postponed
beyond o.

         8. Rounding in Calculations
            ------------------------

         All percentages resulting from any calculation on this Security will be
rounded, if necessary, upward or downward, as appropriate to the next higher or
lower one hundred-thousandth of a percentage point, with five one-millionths of
a percentage point rounded upward (e.g., 9.876545% (or .09876545) being rounded
up to 9.87655% (or .0987655)), and U.S. dollar amounts used in or resulting from
such calculations will be rounded to the nearest cent, with one-half cent or
more being rounded upward.

                    (Face of Security continued on next page)

                                        9

<PAGE>

         9. Corporate Events with Respect to the Reference Entity
            -----------------------------------------------------

         If another entity assumes all or substantially all of the obligations
of the Reference Entity by way of merger, consolidation, amalgamation, transfer
or otherwise, then the Reference Entity, for the purpose of this Security, will
be the new resulting entity.

         10. Role of Calculation Agent
             -------------------------

         The Calculation Agent will be solely responsible for all determinations
and calculations regarding 1-month LIBOR and the rate of interest payable on
this Security in respect of each Interest Period, whether a Credit Event has
occurred, the solicitation of quotations, the calculation of the Redemption
Price and 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 absent manifest
error all determinations and calculations made by the Calculation Agent shall be
final and binding on the Company, the 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.

         11. Payment
             -------

         Payment of any amount payable on this Security 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 and any such payment will
be made to an account designated by the Holder (in writing to the Company and
the Trustee on or before the 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
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, that
payment on the Stated Maturity Date or upon acceleration or redemption 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

                    (Face of Security continued on next page)

                                       10

<PAGE>

payment may be made pursuant to the Applicable Procedures of the Depositary as
permitted in said Indenture.

         12. Holidays
             --------

         Notwithstanding any provision of this Security or of the Indenture, if
any 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 payment may be made
(or such principal or interest may be made available for payment) on the next
succeeding Business Day with the same force and effect as if such 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.

         13. 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.

         14. 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)

                                       11

<PAGE>



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

                                            UBS AG

                                            By   ____________________________
                                                 Name:
                                                 Title:


                                            By   ____________________________
                                                 Name:
                                                 Title:


         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 $o (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 Company as provided in the Indenture at a
redemption price determined by the Calculation Agent in a manner reasonably
calculated to preserve the relative economic position of the Company and the
Holders of Outstanding Securities.

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         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 interest on this
Security as herein provided.

         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 his attorney duly authorized in
writing. Thereupon one or more new Securities of this series and of like

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tenor, of authorized denominations and for the same aggregate Principal 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 is a Global Security and is subject to the provisions of
the Indenture relating to Global Securities, including the limitations in
Section 305 thereof on transfers and exchanges of Global Securities.

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