<PAGE>
                                                                    Exhibit 4.01

         This Subordinated Note is a Global Security within the meaning of the
Indenture hereinafter referred to and is registered in the name of the
Depository named below or a nominee of the Depository. This Subordinated Note is
not exchangeable for Subordinated Notes registered in the name of a Person other
than the Depository or its nominee except in the limited circumstances described
herein and in the Indenture, and no transfer of this Subordinated Note (other
than a transfer of this Subordinated Note as a whole by the Depository to a
nominee of the Depository or by a nominee of the Depository to the Depository or
another nominee of the Depository) may be registered except in the limited
circumstances described herein.

         Unless this certificate is presented by an authorized representative of
The Depository Trust Company, a New York corporation (the "Depository"), to the
Company 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 the Depository (and any
payment is made to Cede & Co. or to such other entity as is requested by an
authorized representative of the Depository), 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.

         THE SUBORDINATED NOTES ARE NOT SAVINGS ACCOUNTS OR DEPOSITS BUT ARE
UNSECURED OBLIGATIONS OF CITIGROUP INC. THE SUBORDINATED NOTES ARE NOT INSURED
BY THE FEDERAL DEPOSIT INSURANCE CORPORATION OR ANY OTHER FEDERAL AGENCY OR
INSTRUMENTALITY.

                                 CITIGROUP INC.
                   6.625% SUBORDINATED NOTES DUE JUNE 15, 2032
REGISTERED                                               REGISTERED

                                                            CUSIP:
                                                             ISIN:
                                                      Common Code:

No. R-                                                           $

         CITIGROUP INC., a Delaware corporation (the "Company", which term
includes any successor Person under the Indenture), for value received, hereby
promises to pay to Cede & Co., or registered assigns, the principal sum of
$__________ on June 15, 2032 and to pay interest thereon from and including June
6, 2002 or from the most recent Interest Payment Date to which interest has been
paid or duly provided for, semi-annually, on June 15 and December 15 of each
year, commencing December 15, 2002, at the rate of 6.625% per annum, until the
principal hereof is paid or made available for payment. The interest 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 Subordinated
Note is registered at the close of business on the Record Date for such
interest, which shall be the May 31 and November 30 (whether or not a Business
Day) immediately preceding such Interest Payment Date.
<PAGE>
         Any such interest not so punctually paid or duly provided for will
forthwith cease to be payable to the holder on such Record Date and may either
be paid to the Person in whose name this Subordinated Note is registered at the
close of business on a subsequent Record Date, such subsequent Record Date to be
not less than five days prior to the date of payment of such defaulted interest,
notice whereof shall be given to holders of Subordinated Notes of this series
not less than 15 days prior to such subsequent 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 Subordinated Notes 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.

         Interest hereon will be calculated on the basis of a 360-day year
comprised of twelve 30-day months.

         If either an Interest Payment Date or the Maturity of the Subordinated
Notes falls on a day that is not a Business Day, such Interest Payment Date or
Maturity will be the next succeeding Business Day. If a date for payment of
interest or principal on the Subordinated Notes falls on a day that is not a
business day in the place of payment, such payment will be made on the next
succeeding business day in such place of payment as if made on the date the
payment was due. No interest will accrue on any amounts payable for the period
from and after the due date for payment of such principal or interest.

         For these purposes, "Business Day" means any day which is a day on
which commercial banks settle payments and are open for general business in The
City of New York.

         Payment of the principal of and interest on this Subordinated Note will
be made at the office or agency of the Trustee maintained for that purpose in
The City of New York.

         Reference is hereby made to the further provisions of this Subordinated
Note 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 or by an authenticating agent on behalf of the Trustee by manual
signature, this Subordinated Note shall not be entitled to any benefit under the
Indenture or be valid or obligatory for any purpose.

                                       2
<PAGE>
         IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed under its corporate seal.

Dated:  June 6, 2002

                                    CITIGROUP INC.

                                    By: Specimen
                                    -----------------
                                    Title:  Treasurer

ATTEST:

By:
-------------------
Assistant Secretary

                                       3
<PAGE>
         This is one of the Subordinated Notes of the series issued under the
within-mentioned Indenture.

Dated:  June 6, 2002

                                    BANK ONE TRUST COMPANY, N.A.
                                    as Trustee

                                    By:_________________________________
                                       Name:
                                       Title:

                                    -or-

                                    CITIBANK, N.A.,
                                    as Authenticating Agent


                                    By:_________________________________
                                       Name:
                                       Title:

                                       4
<PAGE>
         This Subordinated Note is one of a duly authorized issue of Securities
of the Company (the "Subordinated Notes"), issued and to be issued in one or
more series under the Indenture, dated as of April 12, 2001 (the "Indenture"),
between the Company and Bank One Trust Company, N.A., as Trustee (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 Subordinated Notes
and of the terms upon which the Subordinated Notes are, and are to be,
authenticated and delivered. This Subordinated Note is one of the series
designated on the face hereof, initially limited in aggregate principal to
$1,000,000,000.

         The Company covenants and agrees that the indebtedness evidenced by the
Subordinated Notes is subordinate and junior in right of payment to all Senior
Indebtedness (as defined in the Indenture) to the extent provided in the
Indenture, and each holder of Subordinated Notes, by his or her acceptance
thereof, likewise covenants and agrees to the subordination provided in the
Indenture (including Article Fourteen thereof) and shall be bound by the
provisions thereof.

         In the event that the Company shall default in the payment of any
principal of (or premium, if any) or interest on any Senior Indebtedness when
the same becomes due and payable after any applicable grace period, whether at
maturity or at a date fixed for prepayment or by declaration or otherwise, then,
unless and until such default shall have been cured or waived or shall have
ceased to exist, no direct or indirect payment (in cash, property, securities,
by set-off or otherwise) shall be made or agreed to be made on account of the
principal of, or premium, if any, or interest on the indebtedness evidenced by
the Subordinated Notes, or in respect of any redemption, retirement or other
acquisition of any of the Subordinated Notes, except that holders of
Subordinated Notes may receive and retain (x) securities of the Company or any
other corporation provided for by a plan of reorganization or readjustment the
payment of which is subordinate, at least to the extent provided in these
subordination provisions with respect to the indebtedness evidenced by the
Subordinated Notes, to the payment of all Senior Indebtedness at the time
outstanding and to any securities issued in respect thereof under any such plan
of reorganization or readjustment and (y) payments made from a defeasance trust
created pursuant to Article Eleven of the Indenture.

         In the event of:

                  (i) any insolvency, bankruptcy, receivership, liquidation,
         reorganization, readjustment, composition or other similar proceeding
         relating to the Company, its creditors or its property,

                  (ii) any proceeding for liquidation, dissolution or other
         winding up of the Company, voluntary or involuntary, whether or not
         involving insolvency or bankruptcy proceedings,

                                       5
<PAGE>
                  (iii) any assignment by the Company for the benefit of
         creditors, or

                  (iv) any other marshalling of the assets of the Company,

all Senior Indebtedness (including any interest thereon accruing after the
commencement of any such proceedings) shall first be paid in full before any
payment or distribution, whether in cash, securities or other property, shall be
made to any Holder of any of the Subordinated Notes on account thereof (except
as provided in the next sentence). Any payment or distribution, whether in cash,
securities or other property (other than (x) securities of the Company or any
other corporation provided for by a plan of reorganization or readjustment the
payment of which is subordinate, at least to the extent provided in these
subordination provisions with respect to the indebtedness evidenced by the
Subordinated Notes, to the payment of all Senior Indebtedness at the time
outstanding and to any securities issued in respect thereof under any such plan
of reorganization or readjustment and (y) payments made from a defeasance trust
created pursuant to Article Eleven of the Indenture), which would otherwise (but
for these subordination provisions) be payable or deliverable in respect of the
Subordinated Notes shall be paid or delivered directly to the holders of Senior
Indebtedness in accordance with the priorities then existing among such holders
until all Senior Indebtedness (including any interest thereon accruing after the
commencement of any such proceedings) shall have been paid in full.

         If an event of default (as defined in the Indenture) with respect to
Subordinated Notes of this series shall occur and be continuing, the principal
of the Subordinated Notes of this series may be declared due and payable in the
manner and with the effect provided in the Indenture.

         The Indenture contains provisions for defeasance at any time of the
entire indebtedness of this Subordinated Note upon compliance by the Company
with certain conditions set forth in Article Eleven thereof, which provisions
apply to this Subordinated Note.

         The Indenture contains provisions permitting the Company and the
Trustee, without the consent of the holders of Securities, to establish, among
other things, the form and terms of any series of Securities issuable thereunder
by one or more supplemental indentures, and, with the consent of the holders of
not less than a majority of the principal amount of Securities at the time
Outstanding which are affected thereby, to modify the Indenture or any
supplemental indenture or the rights of the holders of Securities of such series
to be affected, provided that no such modification shall, without the consent of
the holder of each Outstanding Security so affected, (x) change the Stated
Maturity of the principal of, or any installment of principal of or interest on,
any Security, or reduce the principal amount thereof or the rate of interest
thereon or any premium thereon, or change any place of payment where, or the
coin or currency in which any Security or any premium or interest thereon is
payable, 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
on or after the Redemption Date) or modify the provisions of the Indenture with
respect to the subordination of the Securities in a manner adverse to the
Securityholders or (y) reduce the aforesaid percentage in principal amount of
the Outstanding Securities of any series, the consent of the holders of which is
required for any supplemental indenture, or the consent of whose holders is
required for any waiver provided for in the

                                       6
<PAGE>
Indenture, or (z) modify certain other provisions of the Indenture, as set forth
in Section 13.02 of the Indenture.

         No reference herein to the Indenture and no provision of this
Subordinated Note 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 Subordinated Note at the times, place and rate, and in the coin
or currency, herein prescribed.

         This Subordinated Note is a Global Security registered in the name of a
nominee of the Depository. This Subordinated Note is exchangeable for
Subordinated Notes registered in the name of a person other than the Depository
or its nominee only in the limited circumstances hereinafter described. Unless
and until it is exchanged in whole or in part for definitive Subordinated Notes
in certificated form, this Subordinated Note may not be transferred except as a
whole by the Depository to a nominee of the Depository or by a nominee of the
Depository to the Depository or another nominee of the Depository.

         The Subordinated Notes represented by this Global Security are
exchangeable for definitive Subordinated Notes in certificated form of like
tenor as such Subordinated Notes in denominations of $1,000 and integral
multiples thereof only if (i) the Depository notifies the Company that it is
unwilling or unable to continue as Depository for the Subordinated Notes or (ii)
the Depository ceases to be a clearing agency registered under the Securities
Exchange Act of 1934, as amended, or (iii) the Company in its sole discretion
decides to allow the Subordinated Notes to be exchanged for definitive
Subordinated Notes in registered form. Any Subordinated Notes that are
exchangeable pursuant to the preceding sentence are exchangeable for
certificated Subordinated Notes issuable in authorized denominations and
registered in such names as the Depository shall direct. As provided in the
Indenture and subject to certain limitations therein set forth, the transfer of
definitive Subordinated Notes in certificated form is registrable in the
register maintained by the Company in The City of New York for such purpose,
upon surrender of the definitive Subordinated Note for registration of transfer
at the office or agency of the registrar, duly endorsed by, or accompanied by a
written instrument of transfer in form satisfactory to the Company and the
registrar duly executed by, the holder thereof or his attorney duly authorized
in writing, and thereupon one or more new Subordinated Notes of this series and
of like tenor, of authorized denominations and for the same aggregate principal
amount, will be issued to the designated transferee or transferees. Subject to
the foregoing, this Subordinated Note is not exchangeable, except for a Global
Security or Global Securities of this issue of the same principal amount to be
registered in the name of the Depository or its nominee.

         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 Subordinated Note 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 Subordinated Note is registered as the
owner hereof for all purposes, whether or

                                       7
<PAGE>
not this Subordinated Note be overdue, and neither the Company, the Trustee nor
any such agent shall be affected by notice to the contrary.

         The Company will pay additional amounts ("Additional Amounts") to the
beneficial owner of any Subordinated Note that is a non-United States person in
order to ensure that every net payment on such Subordinated Note will not be
less, due to payment of U.S. withholding tax, than the amount then due and
payable. For this purpose, a "net payment" on a Subordinated Note means a
payment by the Company or a paying agent, including payment of principal and
interest, after deduction for any present or future tax, assessment or other
governmental charge of the United States. These Additional Amounts will
constitute additional interest on the Subordinated Note.

         The Company will not be required to pay Additional Amounts, however, in
any of the circumstances described in items (1) through (13) below.

         (1)      Additional Amounts will not be payable if a payment on a
                  Subordinated Note is reduced as a result of any tax,
                  assessment or other governmental charge that is imposed or
                  withheld solely by reason of the beneficial owner:

                  (a)      having a relationship with the United States as a
                           citizen, resident or otherwise;

                  (b)      having had such a relationship in the past or

                  (c)      being considered as having had such a relationship.

         (2)      Additional Amounts will not be payable if a payment on a
                  Subordinated Note is reduced as a result of any tax,
                  assessment or other governmental charge that is imposed or
                  withheld solely by reason of the beneficial owner:

                  (a)      being treated as present in or engaged in a trade or
                           business in the United States;

                  (b)      being treated as having been present in or engaged in
                           a trade or business in the United States in the past
                           or

                  (c)      having or having had a permanent establishment in the
                           United States.

         (3)      Additional Amounts will not be payable if a payment on a
                  Subordinated Note is reduced as a result of any tax,
                  assessment or other governmental charge that is imposed or
                  withheld solely by reason of the beneficial owner being or
                  having been, any of the following (as these terms are defined
                  in the Internal Revenue Code of 1986, as amended):

                  (a)      personal holding company;

                  (b)      foreign personal holding company;

                  (c)      foreign private foundation or other foreign
                           tax-exempt organization;

                  (d)      passive foreign investment company;

                  (e)      controlled foreign corporation or

                                       8
<PAGE>
                  (f)      corporation which has accumulated earnings to avoid
                           United States federal income tax.

         (4)      Additional Amounts will not be payable if a payment on a
                  Subordinated Note is reduced as a result of any tax,
                  assessment or other governmental charge that is imposed or
                  withheld solely by reason of the beneficial owner owning or
                  having owned, actually or constructively, 10 percent or more
                  of the total combined voting power of all classes of stock of
                  the Company entitled to vote or by reason of the beneficial
                  owner being a bank that has invested in a Subordinated Note as
                  an extension of credit in the ordinary course of its trade or
                  business.

For purposes of items (1) through (4) above, "beneficial owner" means a
fiduciary, settlor, beneficiary, member or shareholder of the holder if the
holder is an estate, trust, partnership, limited liability company, corporation
or other entity, or a person holding a power over an estate or trust
administered by a fiduciary holder.

         (5)      Additional Amounts will not be payable to any beneficial owner
                  of a Subordinated Note that is a:

                  (a)      fiduciary;

                  (b)      partnership;

                  (c)      limited liability company or

                  (d)      other fiscally transparent entity

                  or that is not the sole beneficial owner of the Subordinated
                  Note, or any portion of the Subordinated Note. However, this
                  exception to the obligation to pay Additional Amounts will
                  only apply to the extent that a beneficiary or settlor in
                  relation to the fiduciary, or a beneficial owner or member of
                  the partnership, limited liability company or other fiscally
                  transparent entity, would not have been entitled to the
                  payment of an Additional Amount had the beneficiary, settlor,
                  beneficial owner or member received directly its beneficial or
                  distributive share of the payment.

         (6)      Additional Amounts will not be payable if a payment on a
                  Subordinated Note is reduced as a result of any tax,
                  assessment or other governmental charge that is imposed or
                  withheld solely by reason of the failure of the beneficial
                  owner or any other person to comply with applicable
                  certification, identification, documentation or other
                  information reporting requirements. This exception to the
                  obligation to pay Additional Amounts will only apply if
                  compliance with such reporting requirements is required by
                  statute or regulation of the United States or by an applicable
                  income tax treaty to which the United States is a party as a
                  precondition to exemption from such tax, assessment or other
                  governmental charge.

         (7)      Additional Amounts will not be payable if a payment on a
                  Subordinated Note is reduced as a result of any tax,
                  assessment or other governmental charge that is

                                       9
<PAGE>
                  collected or imposed by any method other than by withholding
                  from a payment on a Subordinated Note by the Company or a
                  paying agent.

         (8)      Additional Amounts will not be payable if a payment on a
                  Subordinated Note is reduced as a result of any tax,
                  assessment or other governmental charge that is imposed or
                  withheld by reason of a change in law, regulation, or
                  administrative or judicial interpretation that becomes
                  effective more than 15 days after the payment becomes due or
                  is duly provided for, whichever occurs later.

         (9)      Additional Amounts will not be payable if a payment on a
                  Subordinated Note is reduced as a result of any tax,
                  assessment or other governmental charge that is imposed or
                  withheld by reason of the presentation by the beneficial owner
                  of a Subordinated Note for payment more than 30 days after the
                  date on which such payment becomes due or is duly provided
                  for, whichever occurs later.

         (10)     Additional Amounts will not be payable if a payment on a
                  Subordinated Note is reduced as a result of any:

                  (a)      estate tax;

                  (b)      inheritance tax;

                  (c)      gift tax;

                  (d)      sales tax;

                  (e)      excise tax;

                  (f)      transfer tax;

                  (g)      wealth tax;

                  (h)      personal property tax or

                  (i)      any similar tax, assessment or other governmental
                           charge.

         (11)     Additional Amounts will not be payable if a payment on a
                  Subordinated Note is reduced as a result of any tax,
                  assessment, or other governmental charge required to be
                  withheld by any paying agent from a payment of principal or
                  interest on a Subordinated Note if such payment can be made
                  without such withholding by any other paying agent.

         (12)     Additional amounts will not be payable if a payment on a
                  Subordinated Note is reduced as a result of any tax,
                  assessment or other governmental charge that is required to be
                  made pursuant to any European Union directive on the taxation
                  of savings income or any law implementing or complying with,
                  or introduced to conform to, any such directive.

         (13)     Additional Amounts will not be payable if a payment on a
                  Subordinated Note is reduced as a result of any combination of
                  items (1) through (12) above.

                                       10
<PAGE>
         Except as specifically provided herein, the Company will not be
required to make any payment of any tax, assessment or other governmental charge
imposed by any government or a political subdivision or taxing authority of such
government.

         As used in this Subordinated Note, "United States person" means:

         (a)      any individual who is a citizen or resident of the United
                  States;

         (b)      any corporation, partnership or other entity created or
                  organized in or under the laws of the United States;

         (c)      any estate if the income of such estate falls within the
                  federal income tax jurisdiction of the United States
                  regardless of the source of such income and

         (d)      any trust if a United States court is able to exercise primary
                  supervision over its administration and one or more United
                  States persons have the authority to control all of the
                  substantial decisions of the trust.

         Additionally, "non-United States person" means a person who is not a
United States person, and "United States" means the United States of America,
including the States of the United States of America and the District of
Columbia, but excluding its territories and possessions.

         Except as provided below, the Subordinated Notes may not be redeemed
prior to maturity.

         (1)      The Company may, at its option, redeem the Subordinated Notes
                  if:

                  (a)      the Company becomes or will become obligated to pay
                           Additional Amounts as described above;

                  (b)      the obligation to pay Additional Amounts arises as a
                           result of any change in the laws, regulations or
                           rulings of the United States, or an official position
                           regarding the application or interpretation of such
                           laws, regulations or rulings, which change is
                           announced or becomes effective on or after May 30,
                           2002 and

                  (c)      the Company determines, in its business judgment,
                           that the obligation to pay such Additional Amounts
                           cannot be avoided by the use of reasonable measures
                           available to it, other than substituting the obligor
                           under the Subordinated Notes or taking any action
                           that would entail a material cost to the Company.

         (2)      The Company may also redeem the Subordinated Notes, at its
                  option, if:

                  (a)      any act is taken by a taxing authority of the United
                           States on or after May 30, 2002, whether or not such
                           act is taken in relation to the Company or any
                           affiliate, that results in a substantial probability
                           that the Company will or may be required to pay
                           Additional Amounts as described above;

                  (b)      the Company determines, in its business judgment,
                           that the obligation to pay such Additional Amounts
                           cannot be avoided by the use of reasonable measures
                           available to it, other than substituting the obligor
                           under the

                                       11
<PAGE>
                           Subordinated Notes or taking any action that would
                           entail a material cost to the Company and

                  (c)      the Company receives an opinion of independent
                           counsel to the effect that an act taken by a taxing
                           authority of the United States results in a
                           substantial probability that the Company will or may
                           be required to pay the Additional Amounts described
                           above, and delivers to the Trustee a certificate,
                           signed by a duly authorized officer, stating that
                           based on such opinion the Company is entitled to
                           redeem the Subordinated Notes pursuant to their
                           terms.

Any redemption of the Subordinated Notes as set forth in clauses (1) or (2)
above shall be in whole, and not in part, and will be made at a redemption price
equal to 100% of the principal amount of the Subordinated Notes Outstanding plus
accrued interest thereon to the date of redemption. Holders shall be given not
less than 30 days nor more than 60 days prior notice by the Trustee of the date
fixed for such redemption.

         All terms used in this Subordinated Note which are defined in the
Indenture shall have the meanings assigned to them in the Indenture. The
Subordinated Notes are governed by the laws of the State of New York.

                                       12