<PAGE>

                                                                     EXHIBIT 4.5

                              [Face of Debenture]


     The following legend applies if this Security is a Global Security:  Unless
this certificate is presented by an authorized representative of The Depository
Trust Company, a New York corporation ("DTC"), to the Issuer 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 requested by an
authorized representative of DTC (and any payment is made to Cede & Co. or 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.

     This Security is not a deposit or other obligation of a depository
institution and is not insured by the Federal Deposit Insurance Corporation, the
Bank Insurance Fund or any other governmental agency.


CUSIP NO. 949746 CF6                           PRINCIPAL AMOUNT: $______________
REGISTERED NO. ____

                             WELLS FARGO & COMPANY

            7% JUNIOR SUBORDINATED DEBENTURES DUE SEPTEMBER 1, 2031


     WELLS FARGO & COMPANY, a corporation duly organized and existing under the
laws of the State of Delaware (hereinafter called the "Company", which term
includes any successor corporation under the Indenture hereinafter referred to),
for value received, hereby promises to pay to _________________________________
_____________________________________, or registered assigns, the principal sum
of ____________________________________________ ($______________) on September
1, 2031; provided, however, that the Company may accelerate or extend the Stated
Maturity of the principal of this Security subject to the conditions specified
on the reverse hereof. The Company further promises to pay interest on the
principal sum from August 29, 2001 or from the most recent Interest Payment Date
to which interest has been paid or duly provided for quarterly (subject to
deferral as set forth herein) on March 1, June 1, September 1 and December 1 of
each year commencing December 1, 2001 at the rate of 7% per annum, together with
Additional Sums, if any, as provided in Section 1007 of the Indenture, until the
principal hereof is paid or made available for payment; provided, however, that
any overdue installment of interest (after giving effect to any Extension Period
permitted by this Security) shall bear Additional Interest at the rate of 7% per
annum (to the extent that the payment of such interest shall be legally
enforceable), compounded quarterly, from the date such installment was due until
it is paid or made available for payment. The amount of interest payable for any
period less than a full quarterly interest period shall be computed on the basis
of a 360-day year of twelve 30-day months and the actual days elapsed in a
partial month in such period. The amount of interest payable for any full
quarterly interest period shall be computed by dividing the applicable rate per
annum by four. The interest so payable, and punctually paid or duly provided
for, on any Interest Payment Date
<PAGE>

will, as provided in the Indenture, be paid to 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, which shall be the 15/th/
calendar day (whether or not a Business Day, as defined below) next preceding
such Interest Payment Date. If an Interest Payment Date is not a Business Day,
interest on this Security shall be payable on the next day that is a Business
Day, with the same force and effect as if made on such Interest Payment Date,
and without any interest or other payment with respect to the delay. "Business
Day" as used hereinabove is a day other than a Saturday, a Sunday or any other
day on which banking institutions in Minneapolis, Minnesota, Wilmington,
Delaware or New York, New York are authorized or required by law or executive
order to remain closed.

     Any interest not punctually paid or duly provided for will forthwith cease
to be payable to the Holder on such Regular Record Date and 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 Holders of Securities of this series not less than 10
days prior to such Special Record Date, or be paid at any time in any other
lawful manner not inconsistent with the requirements of any securities exchange
on which the Securities of this series may be listed, and upon such notice as
may be required by such exchange, all as more fully provided in the Indenture.

     So long as no Event of Default has occurred and is continuing, the Company
shall have the right, at any time during the term of this Security, from time to
time to defer the payment of interest on this Security for up to 20 consecutive
quarterly interest payment periods with respect to each deferral period (each an
"Extension Period"), during which Extension Period the Company shall have the
right to make a partial payment of interest on any Interest Payment Date, at the
end of which the Company shall pay all interest then accrued and unpaid
including any Additional Interest, as provided below; provided, however, that no
Extension Period shall extend beyond the Maturity of the principal of this
Security and no such Extension Period may end other than at the end of a full
quarterly interest period; and provided, further, however, that during any such
Extension Period, the Company shall not (i) make any payment of principal of or
interest or premium, if any, on or repay, repurchase or redeem any debt
securities of the Company that rank pari passu in all respects with or junior in
interest to this Security (except for any partial payments of interest with
respect to and permitted under the Securities of this series), or (ii) declare
or pay any dividends or distributions on, or redeem, purchase, acquire or make a
liquidation payment with respect to, any of the Company's capital stock (other
than (a) repurchases, redemptions or other acquisitions of shares of capital
stock of the Company in connection with any employment contract, benefit plan or
other similar arrangement with or for the benefit of any one or more employees,
officers, directors, consultants or independent contractors, in connection with
a dividend reinvestment or stockholder stock purchase plan or in connection with
the issuance of capital stock of the Company (or securities convertible into or
exercisable for such capital stock) as consideration in an acquisition
transaction entered into prior to the applicable Extension Period, (b) as a
result of an exchange, redemption or conversion of any class or series of the
Company's capital stock (or any capital stock of a subsidiary of the Company)
for any other class or series of the Company's capital stock or of any class or
series of the Company's indebtedness for any class or series of the Company's
capital stock, (c) the purchase of fractional interests in shares of the
Company's capital stock pursuant to the conversion or exchange provisions of
such capital stock or the security being converted or exchanged, (d) any
declaration of a dividend in connection with any Rights Plan, or the issuance

                                       2
<PAGE>

of rights, stock or other property under any Rights Plan, or the redemption or
repurchase of rights pursuant thereto, (e) payments by the Company under the
Guarantee Agreement, or (f) any dividend in the form of stock, warrants, options
or other rights where the dividend stock or the stock issuable upon exercise of
such warrants, options or other rights is the same stock as that on which the
dividend is being paid or ranks pari passu with or junior to such stock). Prior
to the termination of any such Extension Period, the Company may further defer
the payment of interest, provided that no Extension Period shall exceed 20
consecutive quarterly interest payment periods, extend beyond the Maturity of
the principal of this Security or end other than at the end of a full quarterly
interest period. Upon the termination of any such Extension Period and upon the
payment of all accrued and unpaid interest and any Additional Interest then due
on any Interest Payment Date, the Company may elect to begin a new Extension
Period, subject to the above conditions. No interest or Additional Interest
shall be due and payable during an Extension Period, except at the end thereof,
but each installment of interest that would otherwise have been due and payable
during such Extension Period shall bear Additional Interest (to the extent that
the payment of such interest shall be legally enforceable) at the rate of 7% per
annum, compounded quarterly and calculated as set forth in the first paragraph
of this Security, from the dates on which amounts would otherwise have been due
and payable until paid or made available for payment. The Company shall give the
Holder of this Security and the Trustee notice of its election to begin any
Extension Period at least one Business Day prior to the next succeeding Interest
Payment Date on which interest on this Security would be payable but for such
deferral or, so long as such Securities are held by or on behalf of Wells Fargo
Capital IV, at least one Business Day prior to the earlier of (i) the next
succeeding date on which Distributions on the Capital Trust Securities of such
Issuer Trust would be payable but for such deferral, and (ii) the date on which
the Property Trustee of such Issuer Trust is required to give notice to holders
of such Capital Trust Securities of the record date or the date such
Distributions are payable.

     Payment of interest, including Additional Interest, on this Security will
be made in immediately available funds at the office or agency of the Company
maintained for that purpose in the City of Minneapolis, Minnesota, 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; provided, however, that, at the
option of the Company, payment of interest may be paid by check mailed to the
Person entitled thereto at such Person's last address as it appears in the
Security Register or, upon written request of a Holder of $1,000,000 or more in
aggregate principal amount of Securities of this series not less than 15
calendar days prior to the applicable Interest Payment Date, by wire transfer to
such account as may have been designated by such Person. Payment of principal of
and interest, including Additional Interest, on this Security at Maturity will
be made against presentation of this Security at the office or agency of the
Company maintained for that purpose in the City of Minneapolis, Minnesota.

     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.

     Unless the certificate of authentication hereon has been executed by the
Trustee referred to on the reverse hereof by manual signature or its duly
authorized agent under the Indenture 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.

                                       3
<PAGE>

     IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed under its corporate seal.


DATED: ________________

                                          WELLS FARGO & COMPANY



                                          By:___________________________________
                                             Barbara S. Brett
                                             Assistant Treasurer


[SEAL]
                                          Attest:_______________________________
                                               Laurel A. Holschuh
                                               Secretary



TRUSTEE'S CERTIFICATE OF
AUTHENTICATION
This is one of the Securities of the
series designated therein referred to
in the within-mentioned Indenture.

Bank One Trust Company, N.A.,
     as Trustee

By:____________________________________
   Authorized Signature


OR

Wells Fargo Bank Minnesota, N.A., as
Authenticating Agent for the Trustee



By:____________________________________
   Authorized Signature

                                       4
<PAGE>

                            [Reverse of Debenture]



                             WELLS FARGO & COMPANY


            7% JUNIOR SUBORDINATED DEBENTURES DUE SEPTEMBER 1, 2031


     This Security is one of a duly authorized issue of junior subordinated
securities of the Company (herein called the "Securities"), issued and to be
issued in one or more series under an indenture dated as of August 29, 2001, as
amended or supplemented from time to time (herein called the "Indenture"),
between the Company and Bank One Trust Company, N.A., as Trustee (herein called
the "Trustee", which term includes any successor trustee under the Indenture),
to which Indenture and all indentures supplemental thereto reference is hereby
made for a statement of the respective rights, limitations of rights, duties and
immunities thereunder of the Company, the Trustee and the Holders of the
Securities, and of the terms upon which the Securities are, and are to be,
authenticated and delivered.  This Security is one of the series designated on
the face hereof, limited in aggregate principal amount to $1,340,206,200.

     Subject to any required prior approval of the Primary Federal Regulator,
the Company may at any time, at its option, on or after August 29, 2006, and
subject to the terms and conditions of Article Eleven of the Indenture, redeem
the Securities of this series in whole at any time or in part from time to time,
at a Redemption Price equal to 100% of the principal amount thereof, together,
in the case of any such redemption, with accrued but unpaid interest, including
any Additional Interest, to but excluding the Redemption Date.

     In addition, upon the occurrence and during the continuation of a Tax
Event, an Investment Company Event or a Capital Treatment Event in respect of
Wells Fargo Capital IV, the Company may, at its option, at any time within 90
days of the occurrence and during the continuation of such Tax Event, Investment
Company Event or Capital Treatment Event, as the case may be, subject to any
required prior approval of the Primary Federal Regulator, redeem the Securities
of this series, in whole but not in part, subject to the terms and conditions of
Article Eleven of the Indenture, at a Redemption Price equal to 100% of the
principal amount thereof, together, in the case of any such redemption, with
accrued but unpaid interest, including any Additional Interest, to but excluding
the Redemption Date.

     In addition, if a Tax Event occurs, then the Company will have the right
prior to the termination of Wells Fargo Capital IV, to accelerate the Stated
Maturity of the principal of the Securities of this series to the minimum extent
required in order to allow for the payments of interest (including Additional
Interest) in respect of the Securities of this series to continue to be tax
deductible, but in no event shall the resulting Stated Maturity of the
Securities of this series be less than 15 years from the date of original
issuance thereof. The Stated Maturity shall be accelerated only if, in the
opinion of counsel to the Company, experienced in such matters, (a) after
advancing the Stated Maturity, interest paid on the Securities of this series
will be

                                       5
<PAGE>

deductible for United States federal income tax purposes and (b) accelerating
the Stated Maturity will not result in a taxable event to the holders of the
Capital Trust Securities.

     The Company may extend the Stated Maturity of the principal of the
Securities of this series to a date no later than September 1, 2050 so long as
at the time such election is made and at the time such extension commences (x)
no Event of Default has occurred and is continuing; (y) Wells Fargo Capital IV
is not in arrears on payments of distributions on its Capital Trust Securities
and no deferred distributions have accumulated on its Capital Trust Securities
and (z) the Securities of this series are, and after such extension will be,
rated at least BBB- by Standard & Poor's Ratings Services, at least Baa3 by
Moody's Investors Service, Inc or at least the equivalent by any other
nationally recognized statistical rating organization.

     The Securities of this series are not subject to repayment at the option of
the Holder hereof.  The Securities of this series will not be entitled to any
sinking fund.

     The indebtedness evidenced by the Securities of this series is, to the
extent and in the manner set forth in the Indenture, subordinate and subject in
right of payment to the prior payment in full of the principal of and premium,
if any, and interest on all Senior Debt of the Company, and each Holder of the
Securities of this series, by accepting the same, agrees to and shall be bound
by the provisions of the Indenture with respect hereto. The Securities of this
series shall, not in limitation of the preceding sentence, rank junior to debt
securities issued under the Indenture dated August 30, 1999 between the Company
and Bank One Trust Company, N.A. (as successor in interest to The First National
Bank of Chicago). The Securities of this series shall rank on a parity with all
Trust Related Securities, including without limitation, the Guarantee Agreement
related to the 7% Capital Securities of Wells Fargo Capital IV.

     If an Event of Default, as defined in the Indenture, with respect to
Securities of this series shall occur and be continuing, the principal of the
Securities of this series may be declared due and payable in the manner and with
the effect provided in the Indenture.

     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, acting together. The
Indenture also contains provisions permitting the Holders of a majority in
principal amount of the Securities of all series at the time Outstanding
affected by certain provisions of the Indenture, acting together, on behalf of
the Holders of all Securities of such series, to waive compliance by the Company
with those provisions of the Indenture. Certain past defaults under the
Indenture and their consequences may be waived under the Indenture by the
Holders of a majority in principal amount of the Securities of each series at
the time Outstanding, on behalf of the Holders of all Securities of such series.
All of the rights of the Holders set forth in this paragraph are subject to the
rights of the holders of Capital Trust Securities as set forth in the Indenture.
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.

                                       6
<PAGE>

     The provisions contained in Section 403 and Article Seventeen of the
Indenture for defeasance of the entire indebtedness on this Security and certain
restrictive covenants and certain Events of Default do not apply to this
Security. The provisions contained in Section 401 of the Indenture for
defeasance of the entire indebtedness on this Security in certain circumstances
shall apply to this Security.

     Upon due presentment for registration of transfer of this Security at the
office or agency of the Company in the City of Minneapolis, Minnesota, a new
Security or Securities of this series in authorized denominations of $25 or
integral multiples thereof for an equal aggregate principal amount will be
issued to the transferee in exchange herefor, as provided in the Indenture and
subject to the limitations provided therein and to the limitations described
below, without charge except for any tax or other governmental charge imposed in
connection therewith.

     If this Security is a Global Security, this Security is exchangeable for
definitive Securities in registered form only if (x) the Depositary notifies the
Company that it is unwilling or unable to continue as Depositary for this
Security or if at any time the Depositary ceases to be a clearing agency
registered under the Securities Exchange Act of 1934, as amended, and a
successor depositary is not appointed within 90 days (y) the Company in its sole
discretion determines that this Security shall be exchangeable for definitive
Securities in registered form and notifies the Trustee thereof or (z) an Event
of Default with respect to the Securities represented hereby has occurred and is
continuing.  If this Security is exchangeable pursuant to the preceding
sentence, it shall be exchangeable for definitive Securities in registered form,
bearing interest, including Additional Interest, at the same rate, having the
same date of issuance, redemption provisions, Stated Maturity and other terms
and of authorized denominations aggregating a like amount.

     If this Security is a Global Security, this Security may not be transferred
except as a whole by the Depositary to a nominee of the Depositary or by a
nominee of the Depositary to the Depositary or another nominee of the Depositary
or by the Depositary or any such nominee to a successor of the Depositary or a
nominee of such successor. Except as provided above, owners of beneficial
interests in this global Security will not be entitled to receive physical
delivery of Securities in definitive form and will not be considered the Holders
hereof for any purpose under the Indenture.

     Subject to the rights of holders of Senior Debt of the Company set forth in
this Security and the Indenture referred to above, 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, including any Additional Interest, on this
Security at the times, place and rate, and in the coin or currency, herein
prescribed, except as otherwise provided in this Security and except that in the
event the Company deposits money or Eligible Instruments as provided in Section
401 of the Indenture, such payments will be made only from proceeds of such
money or Eligible Instruments.

     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.

                                       7
<PAGE>

     No recourse shall be had for the payment of the principal of or the
interest, including Additional Interest, on this Security, or for any claim
based hereon, or otherwise in respect hereof, or based on or in respect of the
Indenture or any indenture supplemental thereto, against any incorporator,
stockholder, officer or director, as such, past, present or future, of the
Company or any successor corporation, whether by virtue of any constitution,
statute or rule of law, or by the enforcement of any assessment or penalty or
otherwise, all such liability being, by the acceptance hereof and as part of the
consideration for the issuance hereof, expressly waived and released.

     The Company and, by its acceptance of this Security or a beneficial
interest herein, the Holder of, and any Person that acquires a beneficial
interest in, this Security, agree that for United States Federal, state and
local tax purposes it is intended that this Security constitute indebtedness.

     All terms used in this Security which are defined in the Indenture shall
have the meanings assigned to them in the Indenture unless otherwise defined in
this Security.

                                       8
<PAGE>

                                 ABBREVIATIONS


          The following abbreviations, when used in the inscription on the face
of this instrument, shall be construed as though they were written out in full
according to applicable laws or regulations:

TEN COM   --   as tenants in common

TEN ENT   --   as tenants by the entireties

JT TEN    --   as joint tenants with right
               of survivorship and not
               as tenants in common

UNIF GIFT MIN ACT --  _____________________ Custodian _________________________
                              (Cust)                            (Minor)

Under Uniform Gifts to Minors Act

_____________________________
          (State)

        Additional abbreviations may also be used though not in the above list.


        FOR VALUE RECEIVED, the undersigned hereby sell(s) and transfer(s) unto

Please Insert Social Security or
Other Identifying Number of Assignee

_____________________________


________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________
 (Please print or type name and address including postal zip code of Assignee)

                                       9
<PAGE>

the within Security of WELLS FARGO & COMPANY and does hereby irrevocably
constitute and appoint __________________ attorney to transfer the said Security
on the books of the Company, with full power of substitution in the premises.

Dated: _________________________


                                              __________________________________


                                              __________________________________




NOTICE: The signature to this assignment must correspond with the name as
written upon the face of the within instrument in every particular, without
alteration or enlargement or any change whatever.

                                       10