<PAGE>

                                                                    Exhibit 4.32

                 ============================================




                         EIGHTH SUPPLEMENTAL INDENTURE

                                    between

                             BANK ONE CORPORATION

                                      and

                           THE CHASE MANHATTAN BANK

                        Dated as of September 28, 2001


                ===============================================
<PAGE>

                               TABLE OF CONTENTS
                               -----------------
<TABLE>
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                                                                                                                  Page
                                                                                                                  ----
<S>                                                                                                               <C>
ARTICLE I           DEFINITIONS
     SECTION 1.1.        Definition of Terms....................................................................    2

ARTICLE II          GENERAL TERMS AND CONDITIONS OF THE DEBENTURES
     SECTION 2.1.        Designation and Principal Amount.......................................................    3
     SECTION 2.2.        Maturity...............................................................................    4
     SECTION 2.3         Form and Payment.......................................................................    4
     SECTION 2.4.        Global Debenture.......................................................................    5
     SECTION 2.5.        Interest...............................................................................    6

ARTICLE III         REDEMPTION OF THE DEBENTURES
     SECTION 3.1.        Tax Event, Investment Company Event or Capital Treatment Event Redemption..............    7
     SECTION 3.2.        Optional Redemption by Company.........................................................    7
     SECTION 3.3.        No Sinking Fund........................................................................    8

ARTICLE IV          EXTENSION OF INTEREST PAYMENT PERIOD
     SECTION 4.1.        Extension of Interest Payment Period...................................................    8
     SECTION 4.2.        Notice of Extension....................................................................    8

ARTICLE V           EXPENSES
     SECTION 5.1.        Payment of Expenses....................................................................    9
     SECTION 5.2.        Payment Upon Resignation or Removal....................................................   10

ARTICLE VI          FORM OF DEBENTURE
     SECTION 6.1.        Form of Debenture......................................................................   10

ARTICLE VII         ORIGINAL ISSUE OF DEBENTURES
     SECTION 7.1.        Original Issue of Debentures...........................................................   19

ARTICLE VIII        THE TRUSTEE
     SECTION 8.1.        Certain Duties and Responsibilities....................................................   19

ARTICLE IX          COVENANTS
     SECTION 9.1         Statement as to compliance of the Conditions of Extension of the Maturity Date.........   19
</TABLE>
<PAGE>

<TABLE>
<S>                                                                                                                <C>
ARTICLE X           MISCELLANEOUS
     SECTION 10.1.       Ratification of Indenture..............................................................   20
     SECTION 10.2.       Trustee Not Responsible for Recitals...................................................   20
     SECTION 10.3.       Governing Law..........................................................................   20
     SECTION 10.4.       Separability...........................................................................   20
     SECTION 10.5.       Counterparts...........................................................................   20
</TABLE>
<PAGE>

          EIGHTH SUPPLEMENTAL INDENTURE, dated as of September 28, 2001 (the
"Eighth Supplemental Indenture"), between BANK ONE CORPORATION, a Delaware
------------------------------
corporation (the "Company"), and The Chase Manhattan Bank, as trustee (the
                  -------
"Trustee"), under the Indenture dated as of January 1, 1997 between the Company
--------
and the Trustee (the "Indenture").
                      ---------

          WHEREAS, the Company executed and delivered the Indenture to the
Trustee to provide for the future issuance of the Company's unsecured junior
subordinated debt securities to be issued from time to time in one or more
series as might be determined by the Company under the Indenture, in an
unlimited aggregate principal amount which may be authenticated and delivered as
provided in the Indenture;

          WHEREAS, pursuant to the terms of the Indenture, the Company desires
to provide for the establishment of a new series of its Securities to be known
as its Junior Subordinated Deferrable Interest Debentures due October 15, 2031
(the "Debentures"), the form and substance of such Debentures and the terms,
      ----------
provisions and conditions thereof to be set forth as provided in the Indenture
and this Eighth Supplemental Indenture;

          WHEREAS, BANK ONE Capital VI, a Delaware statutory business trust (the
"Trust"), has offered to the public $500,000,000 aggregate liquidation amount of
 -----
its 7.20% Preferred Securities (the "Preferred Securities") (or $575,000,000
                                     --------------------
aggregate liquidation amount if the underwriters' over-allotment option (the
"Option") is exercised in full), representing undivided beneficial interests in
-------
the assets of the Trust and proposes to invest the proceeds from such offering,
together with the proceeds of the issuance and sale by the Trust to the Company
of $15,463,925 aggregate liquidation amount of its 7.20% Common Securities (or
$17,783,525 if the Option is exercised in full), in $515,463,925 aggregate
principal amount of the Debentures (or $592,783,525 if the Option is exercised
in full); and

          WHEREAS, the Company has requested that the Trustee execute and
deliver this Eighth Supplemental Indenture pursuant to Sections 3.01 and 9.01 of
the Indenture and all requirements necessary to make this Eighth Supplemental
Indenture a valid instrument in accordance with its terms, and to make the
Debentures, when executed by the Company and authenticated and delivered by the
Trustee, the valid obligations of the Company, have been performed, and the
execution and delivery of this Eighth Supplemental Indenture has been duly
authorized in all respects:

          NOW THEREFORE, in consideration of the purchase and acceptance of the
Debentures by the Holders thereof, and for the purpose of setting forth, as
provided in the Indenture, the form and substance of the Debentures and the
terms, provisions and conditions thereof, the Company covenants and agrees with
the Trustee as follows:
<PAGE>

                                   ARTICLE I
                                  DEFINITIONS

SECTION 1.1.   Definition of Terms.
               -------------------

               Unless the context otherwise requires:

               (a)  a term defined in the Indenture has the same meaning when
used in this Eighth Supplemental Indenture;

               (b)  a term defined anywhere in this Eighth Supplemental
Indenture has the same meaning throughout;

               (c)  the singular includes the plural and vice versa;

               (d)  a reference to a Section or Article is to a Section or
Article of this Eighth Supplemental Indenture;

               (e)  headings are for convenience of reference only and do not
affect interpretation;

               (f)  the following terms have the meanings given to them in the
Declaration: (i) Business Day; (ii) Capital Treatment Event; (iii) Clearing
Agency; (iv) Delaware Trustee; (v) Distribution; (vi) Institutional Trustee;
(vii) Institutional Trustee Account; (viii) Investment Company Event; (ix)
Preferred Security Certificate; (x) Regular Trustees; (xi) Special Event; (xii)
Tax Event; and (xiii) Underwriting Agreement;

               (g)  the following terms have the meanings given to them in this
Section 1.1(g):

               "Additional Sums" shall have the meaning set forth in Section
                ---------------
2.5.

               "Bank One Capital Trust" means each of (i) any FCN Capital Trust
                ----------------------
and (ii) BANK ONE Capital I, BANK ONE Capital II, BANK ONE Capital III, BANK ONE
Capital IV, BANK ONE Capital V and BANK ONE Capital VI, each a Delaware business
trust, or any similar trust created for the purpose of issuing preferred
securities in connection with the issuance of Securities under the Indenture.

               "Bank One Guarantee" means any Common Securities Guarantee or
                ------------------
Preferred Securities Guarantee.

               "Compounded Interest" shall have the meaning set forth in Section
                -------------------
4.1.

                                       2
<PAGE>

          "Declaration" means the Amended and Restated Declaration of Trust of
           -----------
BANK ONE Capital VI, a Delaware statutory business trust, dated as of September
28, 2001.

          "Deferred Interest" shall have the meaning set forth in Section 4.1.
           -----------------

          "Depositary", with respect to the Debentures, means The Depository
           ----------
Trust Company or such other successor Clearing Agency for the Preferred
Securities.

          "Dissolution Event" means the liquidation of the Trust by the Regular
           -----------------
Trustees in accordance with the Declaration, and the distribution of the
Debentures held by the Institutional Trustee to the holders of the Trust
Securities issued by the Trust pro rata in accordance with the Declaration.

          "Global Debenture" shall have the meaning set forth in Section 2.4.
           ----------------

          "Maturity Date" shall mean October 15, 2031, unless extended pursuant
           -------------
to Section 2.2(b).

          "Non Book-Entry Preferred Securities" shall have the meaning set forth
           -----------------------------------
in Section 2.4.

          "Redemption Price" shall mean, with respect to any redemption of the
           ----------------
Debentures pursuant to Article III hereof, an amount in cash equal to 100% of
the principal amount to be redeemed plus any accrued and unpaid interest
thereon, including Compounded Interest and Additional Sums, if any, to the date
of such redemption.

          "Trust Securities" shall mean the Preferred Securities and the Common
           ----------------
Securities, collectively.


                                  ARTICLE II
                GENERAL TERMS AND CONDITIONS OF THE DEBENTURES

SECTION 2.1.   Designation and Principal Amount.
               --------------------------------

          There is hereby authorized a series of Securities designated the
"Junior Subordinated Deferrable Interest Debentures due October 15, 2031",
limited in aggregate principal amount to $515,463,925 (or $592,783,525 if the
Option is exercised in full), which amount shall be as set forth in any written
order of the Company for the authentication and delivery of Debentures pursuant
to Section 3.03 of the Indenture.

                                       3
<PAGE>

SECTION 2.2.   Maturity.
               --------

          (a)  The Maturity Date (which shall constitute the Stated Maturity of
the Debentures for purposes of the Indenture), unless extended pursuant to
Section 2.2(b), shall be October 15, 2031, on which the Debentures mature and on
which the principal thereof shall be due and payable together with all accrued
and unpaid interest thereon (including Compounded Interest and Additional Sums,
if any).

          (b)  The Company may extend the Maturity Date of the Debentures to a
date no later than October 15, 2050, so long as at the time such election is
made and at the time the extension commences:

               (i)    no Event of Default with respect to the Debentures has
          occurred and is continuing;

               (ii)   the Trust is not in arrears on payments of distributions
          on the Preferred Securities and no deferred distribution payments on
          the Preferred Securities are accumulated; and

               (iii)  the Debentures are 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 (a "Minimum Rating") and to the
          knowledge of the Company, no downgrading of the Debentures is
          contemplated that would result in not satisfying the Minimum Rating
          requirement.

          (c)  In the event the Company elects to extend the Maturity Date
pursuant to this Section 2.2, the Company shall provide notice of the extension
of the Maturity Date to the Trustee evidenced by an Officers' Certificate, no
more than 90 and no less than 50 days prior to the effectiveness of such
extension, stating that the conditions in Sections 2.2(b)(i), 2.2(b)(ii) and
2.2(b)(iii) have been complied with.

          (d)  The extension of the Maturity Date of the Debentures will
similarly delay the final Distribution on the Trust Securities.

SECTION 2.3.   Form and Payment.
               ----------------

          Except as provided in Section 2.4, the Debentures shall be issued in
fully registered certificated form without interest coupons in minimum
denominations of $25 and in integral multiples thereof.  Principal and interest
on the Debentures issued in certificated form will be payable, the transfer of
such Debentures will be registrable and such Debentures will be exchangeable for
Debentures bearing identical terms and provisions at the office or agency of the
Company as set forth in the last sentence of Section 5.02 of the Indenture;
provided, however,
--------  -------

                                       4
<PAGE>

that payment of interest may be made, at the option of the Company, by check
mailed to the Holder at such address as shall appear in the Security Register or
by wire transfer to an account designated by a Holder in writing not less than
ten days prior to the date of payment. The Company selects each of the City of
New York, New York and the City of Chicago, Illinois as a Place of Payment for
the Debentures and hereby appoints Bank One Trust Company, N.A. as Securities
Registrar for the Debentures. Notwithstanding the foregoing, so long as the
Holder of any Debentures is the Institutional Trustee, the payment of the
principal of and interest (including Compounded Interest and Additional Sums, if
any) on such Debentures held by the Institutional Trustee will be made at such
place and to such account as may be designated by the Institutional Trustee.

SECTION 2.4.   Global Debenture.
               ----------------

          (a)  In connection with a Dissolution Event,

               (i)    the Debentures in certificated form may be presented to
          the Trustee by the Institutional Trustee in exchange for a global
          Debenture in an aggregate principal amount equal to the aggregate
          principal amount of all outstanding Debentures (a "Global Debenture"),
                                                             ----------------
          to be registered in the name of the Depositary, or its nominee, and
          delivered by the Trustee to or upon the order of the Depositary for
          crediting to the accounts of its participants pursuant to the
          instructions of the Regular Trustees.  The Company upon any such
          presentation shall execute a Global Debenture in such aggregate
          principal amount and deliver the same to the Trustee for
          authentication and delivery in accordance with the Indenture and this
          Eighth Supplemental Indenture.  Payments on the Debentures issued as a
          Global Debenture will be made to the Depositary; and

               (ii)   if any Preferred Securities are held in non book-entry
          certificated form, the Debentures in certificated form may be
          presented to the Trustee by the Institutional Trustee and any
          Preferred Security Certificate which represents Preferred Securities
          other than Preferred Securities held by the Clearing Agency or its
          nominee ("Non Book-Entry Preferred Securities") will be deemed to
                    -----------------------------------
          represent beneficial interests in Debentures presented to the Trustee
          by the Institutional Trustee having an aggregate principal amount
          equal to the aggregate liquidation amount of the Non Book-Entry
          Preferred Securities until such Preferred Security Certificates are
          presented to the Security Registrar for transfer or reissuance at
          which time such Preferred Security Certificates will be cancelled and
          a Debenture, registered in the name of the holder of the Preferred
          Security Certificate or the transferee of the holder of such Preferred
          Security Certificate, as the case may be, with an aggregate principal
          amount equal to the aggregate liquidation amount of the Preferred
          Security Certificate cancelled, will be executed by the Company and
          delivered to the Trustee for authentication and delivery in accordance
          with the Indenture and this Eighth Supplemental Indenture.

                                       5
<PAGE>

          Upon the issuance of such Debentures, Debentures with an equivalent
          aggregate principal amount that were presented by the Institutional
          Trustee to the Trustee will be deemed to have been cancelled.

          (b)  A Global Debenture may be transferred, in whole but not in part,
only to another nominee of the Depositary, or to a successor Depositary selected
or approved by the Company or to a nominee of such successor Depositary.

SECTION 2.5.   Interest.
               --------

          (a)  Each Debenture will bear interest at a rate per annum equal to
7.20% (the "Interest Rate") from September 28, 2001 until the principal thereof
            -------------
becomes due and payable, and on any overdue principal at the Interest Rate and
(to the extent that payment of such interest is enforceable under applicable
law) on any overdue installment of interest at the Interest Rate, compounded
quarterly, payable (subject to the provisions of Article Four) quarterly in
arrears on January 15, April 15, July 15 and October 15 of each year commencing
on January 15, 2002 (each such day, an "Interest Payment Date"), to the Person
                                        ---------------------
in whose name such Debenture or any predecessor Debenture is registered, at the
close of business on the regular record date for such interest installment,
which, in respect of any Debentures of which the Institutional Trustee is the
Holder or in the case of a Global Debenture, shall be the close of business on
the Business Day next preceding that Interest Payment Date (as defined below).
Notwithstanding the foregoing sentence, if the Debentures are no longer in book-
entry only form, except if the Debentures are held by the Institutional Trustee,
the regular record dates shall be the January 1, April 1, July 1 and October 1
prior to the applicable Interest Payment Date.

          The term "Interest Period" means each period beginning on, and
                    ---------------
including, September 28, 2001, and ending on, but excluding, the first Interest
Payment Date, and each successive period beginning on, and including, an
Interest Payment Date and ending on, but excluding, the next succeeding Interest
Payment Date.  The amount of interest payable for any Interest Period will be
computed for any full quarterly Interest Period on the basis of a 360-day year
of twelve 30-day months, and for any period shorter than a full quarterly
Interest Period for which interest is computed, interest will be computed on the
basis of the actual number of days elapsed per 90-day quarter.

          (b)  In the event that any Interest Payment Date is not a Business
Day, then payment of interest payable on such date will be made on the next
succeeding day which is a Business Day, in each case with the same force and
effect as if made on such date.

          (c)  If a Tax Event has occurred and is continuing while the
Institutional Trustee is the Holder of any Debentures, and the Trust or the
Institutional Trustee is required to pay any taxes, duties, assessments or
governmental charges of whatever nature (other than withholding taxes) imposed
by the United States, or any other taxing authority, then, in any case, the
Company will pay such additional sums ("Additional Sums") on the Debentures held
                                        ---------------
by the

                                       6
<PAGE>

Institutional Trustee, as shall be required so that the net amounts received and
retained by the Trust and the Institutional Trustee after paying such taxes,
duties, assessments or other governmental charges will not be less than the
amounts the Trust and the Institutional Trustee would have received had the
Trust and the Institutional Trustee not been subject to such taxes, duties,
assessments or other governmental charges as a result of such Tax Event. The
payment of such Additional Sums will be subject to the provisions of Section
5.04 of the Indenture.


                                  ARTICLE III
                         REDEMPTION OF THE DEBENTURES

SECTION 3.1.   Tax Event, Investment Company Event or Capital Treatment Event
               --------------------------------------------------------------
               Redemption.
               ----------

          If a Tax Event, an Investment Company Event or a Capital Treatment
Event has occurred and is continuing then, notwithstanding Section 3.2(a) but
subject to Section 3.2(c), the Company shall have the right upon not less than
30 days nor more than 60 days notice to the Holders of the Debentures to redeem
the Debentures, in whole, but not in part, for cash within 90 days following the
occurrence of such Tax Event, Investment Company Event or Capital Treatment
Event (or, if the approval of the Federal Reserve Board is then required for
such redemption, on such later date as promptly practicable after such approval
is obtained), (the "90 Day Period") at the Redemption Price.

SECTION 3.2.   Optional Redemption by Company.
               ------------------------------

          (a)  Subject to the provisions of Section 3.2(b) and to the provisions
of Article Four of the Indenture, except as otherwise may be specified in this
Eighth Supplemental Indenture, the Company shall have the right to redeem the
Debentures, in whole or in part, from time to time, on or after October 15,
2006, at the Redemption Price.  Any redemption pursuant to this paragraph will
be made upon not less than 30 days nor more than 60 days notice to the Holders
of the Debentures.  If the Debentures are only partially redeemed pursuant to
this Section 3.2, the Debentures will be redeemed pro rata or by lot or by any
                                                  --- ----
other method utilized by the Securities Registrar; provided, that if at the time
                                                   --------
of redemption the Debentures are registered as a Global Debenture, the
Depositary shall determine, in accordance with its procedures, the principal
amount of such Debentures beneficially held by each Holder of Debentures to be
redeemed.

          (b)  If a partial redemption of the Debentures would result in the
delisting of the Preferred Securities issued by the Trust from any national
securities exchange or other organization on which the Preferred Securities are
then listed, the Company shall not be permitted to effect such partial
redemption and may only redeem the Debentures in whole.

                                       7
<PAGE>

          (c)  Any redemption of Debentures pursuant to Section 3.1 or Section
3.2 shall be subject to the Company obtaining the prior approval of the Federal
Reserve, if such approval is then required under applicable law, rules,
guidelines or policies of the Federal Reserve.

SECTION 3.3.   No Sinking Fund.
               ---------------

          The Debentures are not entitled to the benefit of any sinking fund.


                                  ARTICLE IV
                     EXTENSION OF INTEREST PAYMENT PERIOD

SECTION 4.1.   Extension of Interest Payment Period.
               ------------------------------------

          Subject to Section 3.13 of the Indenture, the Company shall have the
right, at any time and from time to time during the term of the Debentures, to
defer payments of interest by extending the interest payment period of such
Debentures for an Extension Period not exceeding 20 consecutive quarters, during
which Extension Period no interest shall be due and payable; provided that no
                                                             --------
Extension Period may end on a date other than an Interest Payment Date or extend
beyond the Maturity Date.  To the extent permitted by applicable law, interest,
the payment of which has been deferred because of the extension of the interest
payment period pursuant to this Section 4.1, will bear interest thereon at the
Interest Rate compounded quarterly for each quarter of the Extension Period
("Compounded Interest").  At the end of the Extension Period, the Company shall
---------------------
pay all interest accrued and unpaid on the Debentures, including any Additional
Sums and Compounded Interest (together, "Deferred Interest") that shall be
                                         -----------------
payable to the Holders of the Debentures in whose names the Debentures are
registered in the Security Register on the record date relating to the Interest
Payment Date on which the Extension Period ends.  Before the termination of any
Extension Period, the Company may further defer payments of interest by further
extending such period, provided that such period, together with all such further
                       --------
extensions thereof, shall not exceed 20 consecutive quarters, or extend beyond
the Maturity Date of the Debentures.  Upon the termination of any Extension
Period and the payment of all Deferred Interest then due, the Company may
commence a new Extension Period, subject to the foregoing requirements.  No
interest shall be due and payable during an Extension Period, except at the end
thereof.

SECTION 4.2.   Notice of Extension.
               -------------------

          (a)  If the Institutional Trustee is the only registered Holder of the
Debentures at the time the Company selects an Extension Period, the Company
shall give written notice to the Regular Trustees, the Institutional Trustee and
the Trustee of its selection of such Extension Period at least one Business Day
before the earlier of (i) the next succeeding date on which Distributions on the
Trust Securities issued by the Trust are payable, or (ii) the date the Trust is
required to give notice of the record date, or the date such Distributions are
payable, to the New

                                       8
<PAGE>

York Stock Exchange or other applicable self-regulatory organization or to
holders of the Preferred Securities issued by the Trust, but in any event at
least one Business Day before such record date.

          (b)  If the Institutional Trustee is not the only Holder of the
Debentures at the time the Company selects an Extension Period, the Company
shall give the Holders of the Debentures and the Trustee written notice of its
selection of such Extension Period at least 10 Business Days before the earlier
of (i) the next succeeding Interest Payment Date, or (ii) the date the Company
is required to give notice of the record or payment date of such interest
payment to any applicable self-regulatory organization or to Holders of the
Debentures.

          (c)  The quarter in which any notice is given pursuant to paragraphs
(a) or (b) of this Section 4.2 shall be counted as one of the 20 quarters
permitted in the maximum Extension Period permitted under Section 4.1.


                                   ARTICLE V
                                   EXPENSES

SECTION 5.1.   Payment of Expenses.
               -------------------

          In connection with the offering, sale and issuance of the Debentures
to the Institutional Trustee and in connection with the sale of the Trust
Securities by the Trust, the Company, in its capacity as borrower with respect
to the Debentures, shall:

          (a)  pay all costs and expenses relating to the offering, sale and
issuance of the Debentures, including commissions to the underwriters payable
pursuant to the Underwriting Agreement and compensation of the Trustee under the
Indenture in accordance with the provisions of Section 8.07 of the Indenture;

          (b)  pay all costs and expenses of the Trust (including, but not
limited to, costs and expenses relating to the organization of the Trust, the
offering, sale and issuance of the Trust Securities (including commissions to
the underwriters in connection therewith), the fees and expenses of the
Institutional Trustee and the Delaware Trustee, the costs and expenses relating
to the operation of the Trust, including without limitation, costs and expenses
of accountants, attorneys, statistical or bookkeeping services, expenses for
printing and engraving and computing or accounting equipment, paying agent(s),
registrar(s), transfer agent(s), duplicating, travel and telephone and other
telecommunications expenses and costs and expenses incurred in connection with
the acquisition, financing, and disposition of Trust assets);

          (c)  be primarily and fully liable for any indemnification obligations
arising with respect to the Declaration; and

                                       9
<PAGE>

          (d)  pay any and all taxes (other than United States withholding taxes
attributable to the Trust or its assets) and all liabilities, costs and expenses
with respect to such taxes of the Trust.

SECTION 5.2.   Payment Upon Resignation or Removal.
               -----------------------------------

          Upon termination of this Eighth Supplemental Indenture or the
Indenture or the removal or resignation of the Trustee, unless otherwise stated,
the Company shall pay to the Trustee all amounts accrued under Section 8.07 of
the Indenture to the date of such termination, removal or resignation.  Upon
termination of the Declaration or the removal or resignation of the Delaware
Trustee or the Institutional Trustee, as the case may be, pursuant to Sections
10.4 and 10.6 of the Declaration, the Company shall pay to the Delaware Trustee
or the Institutional Trustee, as the case may be, all amounts accrued under said
Sections to the date of such termination, removal or resignation.

                                  ARTICLE VI
                               FORM OF DEBENTURE

SECTION 6.1.   Form of Debenture.
               -----------------

          The Debentures and the Trustee's Certificate of Authentication to be
endorsed thereon are to be substantially in the following forms:

                          (FORM OF FACE OF DEBENTURE)

          [IF THE DEBENTURE IS TO BE A GLOBAL DEBENTURE, INSERT - This Debenture
is a Global Debenture within the meaning of the Indenture hereinafter referred
to and is registered in the name of a Depositary or a nominee of a Depositary.
This Debenture is exchangeable for Debentures registered in the name of a person
other than the Depositary or its nominee only in the limited circumstances
described in the Indenture, and no transfer of this Debenture (other than a
transfer of this Debenture 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) may be registered except in limited circumstances.

     Unless this Debenture is presented by an authorized representative of The
Depository Trust Company (55 Water Street, New York, New York) to the issuer or
its agent for registration of transfer, exchange or payment, and any Debenture
issued is registered in the name of Cede & Co. or such other name as requested
by an authorized representative of The Depository Trust Company and any payment
hereon is made to Cede & Co., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE
OR OTHERWISE BY A PERSON IS WRONGFUL since the registered owner hereof, Cede &
Co., has an interest herein.]

                                      10
<PAGE>

No.                                                          CUSIP No. 06423AAP8
                             BANK ONE CORPORATION

                           7.20% JUNIOR SUBORDINATED
                         DEFERRABLE INTEREST DEBENTURE
                             DUE October 15, 2031

          BANK ONE CORPORATION, a Delaware corporation (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 _____________ Dollars ($___________) on October
15, 2031 and to pay interest on said principal sum from September 28, 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) in
arrears on January 15, April 15, July 15 and October 15 of each year commencing
January 15, 2002 (each such date, an "Interest Payment Date"), at the rate of
                                      ---------------------
7.20% per annum (the "Interest Rate") until the principal hereof shall have
                      -------------
become due and payable, and on any overdue principal and premium, if any, at the
Interest Rate and (without duplication and to the extent that payment of such
interest is enforceable under applicable law) on any overdue installment of
interest at the Interest Rate compounded quarterly.  The Company may extend the
Maturity Date of this Debenture to a date no later than October 15, 2050, so
long as at the time such election is made certain conditions described in the
Indenture (hereinafter referred to) are met by the Company.  The amount of
interest payable on any Interest Payment Date (as defined below) shall be
calculated as provided in the Indenture.  In the event that any Interest Payment
Date is not a Business Day, then payment of interest payable on such date will
be made on the next succeeding day that is a Business Day, in each case with the
same force and effect as if made on such date.  The interest installment so
payable, and punctually paid or duly provided for, on any Interest Payment Date
will, as provided in the Indenture, be paid to the person in whose name this
Debenture (or one or more Predecessor Securities, as defined in said Indenture)
is registered at the close of business on the regular record date for such
interest installment, which shall be the close of business on the first business
day next preceding such Interest Payment Date.   If pursuant to the provisions
of the Indenture the Debentures are no longer represented by a Global Debenture,
except if the Debentures are held by the Institutional Trustee, the regular
record date shall be the close of business on the January 1, April 1, July 1 and
October 1 next preceding such Interest Payment Date, as applicable.  Any such
interest installment not punctually paid or duly provided for shall forthwith
cease to be payable to the registered Holders on such regular record date and
may be paid to the Person in whose name this Debenture (or one or more
Predecessor Securities) is registered at the close of business on a special
record date to be fixed by the Trustee for the payment of such defaulted
interest, notice whereof shall be given to the registered Holders of Debentures
not less than 10 days prior to such special record date, or may be paid at any
time in any other lawful manner not inconsistent with the requirements of any
securities exchange on which the Debentures may be listed, and upon such notice
as may be required by such exchange, all as more fully provided in the
Indenture.  The principal of (and premium, if any) and the interest on this
Debenture shall be payable at the office or agency of the Trustee maintained for

                                      11
<PAGE>

that purpose in any coin or currency of the United States of America that at the
time of payment is legal tender for payment of public and private debts;
provided, however, that payment of interest may be made, at the option of the
--------  -------
Company, by check mailed to the registered Holder at such address as shall
appear in the Security Register or by wire transfer to an account designated by
a Holder in writing not less than ten days prior to the date of payment.
Notwithstanding the foregoing, so long as the Holder of this Debenture is the
Institutional Trustee, the payment of the principal of (and premium, if any) and
interest on this Debenture will be made at such place and to such account as may
be designated by the Institutional Trustee.

          The indebtedness evidenced by this Debenture is, to the extent
provided in the Indenture, subordinate and junior in right of payment to the
prior payment in full of all Senior Indebtedness and General Obligations, and
this Debenture is issued subject to the provisions of the Indenture with respect
thereto. Each Holder of this Debenture, by accepting the same, (a) agrees to and
shall be bound by such provisions, (b) authorizes and directs the Trustee on his
or her behalf to take such action as may be necessary or appropriate to
acknowledge or effectuate the subordination so provided and (c) appoints the
Trustee his or her attorney-in-fact for any and all such purposes. Each Holder
hereof, by his or her acceptance hereof, hereby waives all notice of the
acceptance of the subordination provisions contained herein and in the Indenture
by each holder of Senior Indebtedness and creditor in respect of General
Obligations, whether now outstanding or hereafter incurred, and waives reliance
by each such holder or creditor upon said provisions.

          This Debenture shall not be entitled to any benefit under the
Indenture hereinafter referred to, or be valid or become obligatory for any
purpose until the Certificate of Authentication hereon shall have been signed by
or on behalf of the Trustee.

          THIS DEBENTURE IS NOT A SAVINGS OR DEPOSIT ACCOUNT OR OTHER OBLIGATION
OF A BANK AND IS NOT INSURED BY THE FEDERAL DEPOSIT INSURANCE CORPORATION OR ANY
OTHER GOVERNMENTAL AGENCY.

          The provisions of this Debenture are continued on the reverse side
hereof and such continued provisions shall for all purposes have the same effect
as though fully set forth at this place.

                                      12
<PAGE>

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

                                        BANK ONE CORPORATION

                                        By:___________________________________
                                        Name:
                                        Title:  Chairman of the Board


Attest:

By:___________________________
Name:
Title:  Secretary



                    (FORM OF CERTIFICATE OF AUTHENTICATION)

                         CERTIFICATE OF AUTHENTICATION

          This is one of the Securities of the series designated therein
referred to in the within-mentioned Indenture.


The Chase Manhattan Bank,
 as Trustee


By_____________________________
 Authorized Officer



Dated:

                                      13
<PAGE>

                        (FORM OF REVERSE OF DEBENTURE)

          This Debenture is one of a duly authorized series of securities of the
Company (herein sometimes referred to as the "Securities"), all issued or to be
                                              ----------
issued in one or more series under and pursuant to an Indenture dated as of
January 1, 1997, duly executed and delivered between the Company and The Chase
Manhattan Bank, as Trustee (the "Trustee"), as heretofore supplemented and as
                                 -------
supplemented by the Eighth Supplemental Indenture dated as of September 28,
2001, between the Company and the Trustee (the Indenture as so supplemented, the
"Indenture"), to which Indenture and all indentures supplemental thereto
 ---------
reference is hereby made for a description of the rights, limitations of rights,
obligations, duties and immunities thereunder of the Trustee, the Company and
the Holders of the Securities.  By the terms of the Indenture, the Securities
are issuable in series that may vary as to amount, date of maturity, rate of
interest and in other respects as provided in the Indenture.  This Security is
one of the series designated on the face hereof (the "Debentures") and is
                                                      ----------
limited in aggregate principal amount as specified in said Eighth Supplemental
Indenture.

          Upon the occurrence and continuation of a Tax Event, Investment
Company Event or Capital Treatment Event, the Company shall have the right,
subject to certain conditions set forth in the Indenture, to redeem this
Debenture in whole, but not in part, at the Redemption Price within 90 days
following the occurrence of such Tax Event, Investment Company Event or Capital
Treatment Event (or, if the prior approval of the Board of Governors of the
Federal Reserve System (the "Federal Reserve") is then required, on such later
                             ---------------
date as promptly as practicable after such approval is obtained).  In addition,
the Company shall have the right to redeem this Debenture, in whole or in part,
at any time on or after October 15, 2006, at the Redemption Price (any of the
foregoing redemptions an "Optional Redemption").  The "Redemption Price" means
                          -------------------          ----------------
an amount in cash equal to 100% of the principal amount together with any
accrued and unpaid interest thereon, including Additional Sums and Compounded
Interest, if any, to the date of such redemption.  Any redemption pursuant to
this paragraph will be made upon not less than 30 days nor more than 60 days
notice.  If the Debentures are only partially redeemed by the Company pursuant
to an Optional Redemption, the Debentures will be redeemed pro rata or by lot or
                                                           --- ----
by any other method utilized by the Securities Registrar; provided that if, at
the time of redemption, the Debentures are registered as a Global Debenture, the
Depositary shall determine the principal amount of such Debentures beneficially
held by each Debenture Holder to be redeemed in accordance with its procedures.

          In the event of redemption of this Debenture in part only, a new
Debenture or Debentures for the unredeemed portion hereof will be issued in the
name of the Holder hereof upon the cancellation hereof.

          Notwithstanding the foregoing, any redemption of Debentures by the
Company shall be subject to the prior approval of the Federal Reserve, if such
approval is then required under applicable law, rules, guidelines or policies of
the Federal Reserve.

                                      14
<PAGE>

          In case an Event of Default, as defined in the Indenture, shall have
occurred and be continuing, the principal of all of the Debentures may be
declared, and upon such declaration shall become, due and payable, in the
manner, with the effect and subject to the conditions provided in the Indenture.

          The Indenture contains provisions permitting the Company and the
Trustee, with the consent of the Holders of not less than a majority in
aggregate principal amount of the Outstanding Securities of all series affected
(acting as one class), to execute supplemental indentures for the purpose of
adding any provisions to or changing in any manner or eliminating any of the
provisions of the Indenture or of any supplemental indenture or of modifying in
any manner the rights of the Holders of the Securities; provided, however, that
no such supplemental indenture shall (i) change the Maturity of the principal
of, or the Stated Maturity of any installment of interest (or premium, if any)
on, any Outstanding Security, or reduce the principal amount thereof or any
premium thereon or the rate of interest thereon, or change the obligations of
the Company to pay additional amounts pursuant to Section 5.04 of the Indenture,
or to reduce the amount of principal of an Original Issue Discount Security that
would be due and payable upon a declaration of acceleration of the Maturity
thereof, or change the method of calculating interest thereon or the coin or
currency in which any Security (or premium, if any, thereon) or the interest
thereon is payable, or reduce the minimum rate of interest thereon, or impair
the right to institute suit for the enforcement of any such payment on or after
the Stated Maturity thereof (or, in the case of redemption or repayment, on or
after the Redemption Date or Repayment Date); or (ii) reduce the percentage in
principal amount of the Outstanding Securities of any series, the Holders of
which are required to consent to any such supplemental indenture or to waive
certain defaults thereunder and their consequences provided for in the Indenture
or to reduce the requirements of the Indenture for a quorum at meetings of
Holders of Securities; or (iii) change the obligations of the Company to
maintain certain offices or agencies as required by the Indenture; or (iv)
modify any of the provisions of the Indenture relating to supplemental
indentures or the waiver of defaults, except to increase any such percentage or
to provide that certain other provisions of the Indenture cannot be modified or
waived, without the consent of the Holders of each Security then outstanding and
affected thereby.  The Indenture also contains provisions permitting the Holders
of a majority in aggregate principal amount of the Outstanding Securities of any
series affected thereby, on behalf of all of the Holders of the Securities of
such series, to waive any past default in the performance of any of the
covenants contained in the Indenture, or established pursuant to the Indenture
with respect to such series, and its consequences, except a default in the
payment of the principal of, premium, if any, or interest on any of the
Securities of such series.  Any such consent or waiver by the registered Holder
of this Debenture (unless revoked as provided in the Indenture) shall be
conclusive and binding upon such Holder and upon all future Holders and owners
of this Debenture and of any Debenture issued in exchange therefor or in place
hereof (whether by registration of transfer or otherwise), irrespective of
whether or not any notation of such consent or waiver is made upon this
Debenture.

                                      15
<PAGE>

          No reference herein to the Indenture and no provision of this
Debenture or of the Indenture shall alter or impair the obligation of the
Company, which is absolute and unconditional, to pay the principal of and
premium, if any, and interest on this Debenture at the time and place and at the
rate and in the money herein prescribed.

          So long as no Event of Default has occurred and is continuing, the
Company shall have the right, at any time and from time to time during the term
of the Debentures, to defer payments of interest by extending the interest
payment period of such Debentures for up to 20 consecutive quarters (an
"Extension Period"), at the end of which period the Company shall pay all
-----------------
interest then accrued and unpaid (together with interest thereon at the Interest
Rate to the extent that payment of such interest is enforceable under applicable
law); provided that no Extension Period may end on a day other than an Interest
      -------- ----
Payment Date or last beyond the Maturity Date of the Debentures.  Before the
termination of any such Extension Period, the Company may further extend such
Extension Period, provided that such Extension Period together with all such
further extensions thereof shall not exceed 20 consecutive quarters or extend
beyond the Maturity Date of the Debentures.  Upon the termination of any such
Extension Period and the payment of all accrued and unpaid interest and any
additional amounts then due, the Company may commence a new Extension Period,
subject to the foregoing requirements.

          During any such Extension Period, the Company shall not, and shall not
permit any Subsidiary to, (i) 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, or (ii) make any payment of principal of or
interest or premium, if any, on or repay, repurchase or redeem any debt security
of the Company that ranks pari passu in all respects with or junior in interest
to the Debentures or make any guarantee payments with respect to any guarantee
by the Company of the debt securities of any Subsidiary of the Company that by
their terms rank pari passu in all respects with or junior in interest to the
Debentures (other than (a) dividends or distributions in Common Stock, (b) any
declaration of a dividend in connection with the implementation of a Rights
Plan, the issuance of any Common Stock of any class or series of preferred stock
of the Company under any Rights Plan or the repurchase of any rights distributed
pursuant to a Rights Plan, (c) payments under any Bank One Guarantee which is
for the benefit of the holders of Preferred Securities or Common Securities
issued by the Trust, (d) purchases of Common Stock related to the issuance of
Common Stock under any of the Company's benefit plans for its directors,
officers or employees and (e) obligations under any dividend reinvestment and
stock purchase plan).

          Subject to the prior approval of the Federal Reserve if such approval
is then required under applicable law, rules, guidelines or policies of the
Federal Reserve, the Company will have the right at any time to liquidate the
Trust and cause the Debentures to be distributed to the holders of the Trust
Securities in liquidation of the Trust.

          As provided in the Indenture and subject to certain limitations
therein set forth, this Debenture is transferable by the registered Holder
hereof on the Security Register of the

                                      16
<PAGE>

Company, upon surrender of this Debenture for registration of transfer at the
office or agency of the Trustee in the City and State of New York or the City of
Chicago, Illinois accompanied by a written instrument or instruments of transfer
in form satisfactory to the Company and the Securities Registrar duly executed
by the registered Holder hereof or his attorney duly authorized in writing, and
thereupon one or more new Debentures of authorized denominations and for the
same aggregate principal amount will be issued to the designated transferee or
transferees. No service charge will be made for any such transfer, but the
Company may require payment of a sum sufficient to cover any tax or other
governmental charge payable in relation thereto.

          Prior to due presentment for registration of transfer of this
Debenture, the Company, the Trustee, any paying agent and the Security Registrar
may deem and treat the registered holder hereof as the owner hereof (whether or
not this Debenture shall be overdue and notwithstanding any notice of ownership
or writing hereon made by anyone other than the Security Registrar) for the
purpose of receiving payment of or on account of the principal hereof and
premium, if any, and (subject to Section 3.07 of the Indenture) interest due
hereon and for all other purposes, and neither the Company nor the Trustee nor
any paying agent nor any Security Registrar shall be affected by any notice to
the contrary.

          No recourse shall be had for the payment of the principal of or the
interest on this Debenture, or for any claim based hereon, or otherwise in
respect hereof, or based on or in respect of the Indenture, against any
incorporator, stockholder, officer or director, past, present or future, as
such, of the Company or of any predecessor or 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 Debentures are issuable only in registered form without coupons
in denominations of $25 and any integral multiple thereof.]  [This Global
Debenture is exchangeable for Debentures in definitive form only under certain
limited circumstances set forth in the Indenture.  Debentures so issued are
issuable only in registered form without coupons in denominations of $25 and any
integral multiple thereof.]  As provided in the Indenture and subject to certain
limitations herein and therein set forth, Debentures of this series [so issued]
are exchangeable for a like aggregate principal amount of Debentures of a
different authorized denomination, as requested by the Holder surrendering the
same.

          All terms used in this Debenture that are defined in the Indenture
shall have the meanings assigned to them in the Indenture.

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

                                      17
<PAGE>

                                  ARTICLE VII
                         ORIGINAL ISSUE OF DEBENTURES

SECTION 7.1.   Original Issue of Debentures.
               ----------------------------

          Debentures in the aggregate principal amount of $515,463,925 (or
$592,783,525 if the Option is exercised in full) may, upon execution of this
Eighth Supplemental Indenture, be executed by the Company and delivered to the
Trustee for authentication as provided in Sections 3.01 and 3.03 of the
Indenture.

                                 ARTICLE VIII
                                  THE TRUSTEE

SECTION 8.1    Certain Duties and Responsibilities
               -----------------------------------

          Within ten calendars days after the receipt of written notice issued
by the Company of the extension of the Maturity Date pursuant to Section 2.2(c),
the Trustee shall:

          (a)  transmit by mail to all Holders of the Debentures a notice of the
extension of the Maturity Date specifying the extended date of maturity; and

          (b)  transmit by mail to the Institutional Trustee a notice of the
extension of the Maturity Date specifying the extended date of maturity.


                                  ARTICLE IX
                                   COVENANTS

SECTION 9.1    Statement as to Compliance of the Conditions of Extension of the
               ----------------------------------------------------------------
          Maturity Date
          -------------

          If, after the Company elects to extend the Maturity Date and notifies
the Trustee thereof, and at or prior to the time such extension commences, the
Company is no longer compliant with any of the conditions set forth in Sections
2.2(b)(i), 2.2(b)(ii) and 2.2(b)(iii), the Company will promptly deliver a
notice to the Trustee stating that the Company is no longer compliant with the
conditions set forth in Sections 2.2(b)(i), 2.2(b)(ii) and 2.2(b)(iii)
specifying the certain condition or conditions with respect to which the Company
is no longer compliant.

                                      18
<PAGE>

                                   ARTICLE X
                                 MISCELLANEOUS

SECTION 10.1.  Ratification of Indenture.
               -------------------------

          The Indenture, as supplemented by this Eighth Supplemental Indenture,
is in all respects ratified and confirmed, and this Eighth Supplemental
Indenture shall be deemed part of the Indenture in the manner and to the extent
herein and therein provided.

SECTION 10.2.  Trustee Not Responsible for Recitals.
               ------------------------------------

          The recitals herein contained are made by the Company and not by the
Trustee, and the Trustee assumes no responsibility for the correctness thereof.
The Trustee makes no representation as to the validity or sufficiency of this
Eighth Supplemental Indenture.

SECTION 10.3.  Governing Law.
               -------------

          This Eighth Supplemental Indenture and each Debenture shall be
construed in accordance with and governed by the laws of the State of New York.

SECTION 10.4.  Separability.
               ------------

          In case any one or more of the provisions contained in this Eighth
Supplemental Indenture or in the Debentures shall for any reason be held to be
invalid, illegal or unenforceable in any respect, such invalidity, illegality or
unenforceability shall not affect any other provisions of this Eighth
Supplemental Indenture or of the Debentures, but this Eighth Supplemental
Indenture and the Debentures shall be construed as if such invalid or illegal or
unenforceable provision had never been contained herein or therein.

SECTION 10.5.  Counterparts.
               ------------

          This Eighth Supplemental Indenture may be executed in any number of
counterparts each of which shall be an original; but such counterparts shall
together constitute but one and the same instrument.

                                      19
<PAGE>

          IN WITNESS WHEREOF, the parties hereto have caused this Eighth
Supplemental Indenture to be duly executed and attested, as of the day and year
first above written.

                                             BANK ONE CORPORATION


                                             By:________________________________
                                              Name:  Michael J. Cavanagh
                                              Title: Treasurer

Attest:


By:______________________________
 Name:  Sharon A. Renchof
 Title: Assistant Secretary


                                             THE CHASE MANHATTAN BANK,
                                              as Trustee


                                             By:________________________________
                                              Name:  Natalia Rodriguez
                                              Title: Assistant Vice President

Attest:


By: _____________________________

                                      20