<DOCUMENT>
<TYPE>EX-4
<SEQUENCE>3
<FILENAME>a2100738zex-4.txt
<DESCRIPTION>EXHIBIT 4
<TEXT>
<Page>
                                                                   EXHIBIT 4(aa)

    UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY (55 WATER STREET, NEW YORK, NEW YORK) 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 SUCH OTHER NAME AS REQUESTED
BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT
IS MADE TO CEDE & CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF,
CEDE & CO., HAS AN INTEREST HEREIN.

                  INTERNATIONAL BUSINESS MACHINES CORPORATION
                            MEDIUM-TERM MASTER NOTE
                                    (SENIOR)

                                              [Date]

R-

                              UP TO $

REGISTERED

    INTERNATIONAL BUSINESS MACHINES CORPORATION, a New York corporation (the
"Company"), for value received, hereby promises to pay to CEDE & CO. or its
registered assigns: on each maturity date, extended maturity date, redemption
date, repayment date, and any other date specified pursuant to terms referenced
hereby, as applicable, of each obligation identified on the records of the
Company (which records are maintained by JPMorgan Chase Bank (the "Paying
Agent") or specified pursuant to terms referenced hereby, the principal amount
(and premium, if any) then due and payable for each such obligation, and to pay
interest thereon on each Interest Payment Date or as specified pursuant to terms
referenced hereby.

    REFERENCE IS HEREBY MADE TO THE FURTHER PROVISIONS OF THIS MASTER 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, AND TO THE TERMS OF THE
PROSPECTUS, PROSPECTUS SUPPLEMENT AND PRICING SUPPLEMENTS PREPARED BY THE
COMPANY AND ON FILE WITH THE SECURITIES AND EXCHANGE COMMISSION WHICH CONTAIN
FURTHER INFORMATION WITH RESPECT TO THE OBLIGATIONS OF THE COMPANY REPRESENTED
BY THIS MASTER NOTE.

    This Master Note is a valid and binding obligation of the Company.

    Unless the certificate of authentication hereon has been manually executed
by or on behalf of the Trustee under the Indenture between the Company and
JPMorgan Chase Bank, as Trustee, dated as of October 1, 1993, as supplemented by
the First Supplemental Indenture thereto dated as of December 15, 1995
(collectively, the "Indenture"), this Master Note shall not be entitled to any
benefit under the Indenture, or be valid or obligatory for any purpose.

    IN WITNESS WHEREOF, INTERNATIONAL BUSINESS MACHINES CORPORATION has caused
this Master Note to be signed by facsimile by its duly authorized officers and
has caused a facsimile of its corporate seal to be affixed hereunto or imprinted
hereon.

<Table>
<S>                                            <C>  <C>
                                               INTERNATIONAL BUSINESS MACHINES CORPORATION,

                                               By:
                                                    ------------------------------------------------

                                               By:
                                                    ------------------------------------------------
</Table>

[Seal]
<Page>
                    TRUSTEE'S CERTIFICATE OF AUTHENTICATION

    This is one of the Notes issued under the within-mentioned Indenture.

<Table>
<S>                                                       <C>  <C>
Dated:                                                    JPMorgan Chase Bank,
                                                          as Trustee

                                                          By:
                                                               ---------------------------------------
                                                                         Authorized Signatory
</Table>

                            [REVERSE OF MASTER NOTE]

    This Master Note constitutes a series of unsecured notes of the Company
(hereinafter called the "Securities"), to be issued under an indenture dated as
of October 1, 1993, duly executed and delivered by the Company to JPMorgan Chase
Bank as trustee (hereinafter called the "Trustee"), as supplemented by the First
Supplemental Indenture thereto dated as of December 15, 1995, between the
Company and the Trustee, as trustee (hereinafter called the "Indenture") to
which Indenture and all indentures supplemental thereto reference is hereby made
for a description of the respective rights and duties thereunder of the Trustee,
the Company and the holders of the Securities.

    In case an Event of Default with respect to the Securities issued hereunder,
as defined in the Indenture, shall have occurred and be continuing, the
principal hereof together with interest accrued thereon, if any, 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 Securities at the time outstanding of all series to be
affected (acting as one class), to execute supplemental indentures adding any
provisions to or changing in any manner or eliminating any of the provisions of
the Indenture or of any supplemental indenture or modifying in any manner the
rights of the holders of the Securities of such series to be affected; provided,
however, that no such supplemental indenture shall, among other things,
(i) change the fixed maturity of the principal of, or any installment of
principal of or interest on, or the currency of payment of, any Security;
(ii) reduce the principal amount thereof or the rate of interest thereon or any
premium payable upon the redemption thereof; (iii) impair the right to institute
suit for the enforcement of any such payment on or after the fixed maturity
thereof (or, in the case of redemption, on or after the redemption date);
(iv) reduce the percentage in principal amount of the outstanding Securities of
any series, the consent of whose holders is required for any such supplemental
indenture, or the consent of whose holders is required for any waiver (of
compliance with certain provisions of the Indenture or certain defaults
thereunder and their consequences) provided for in the Indenture; (v) change any
obligation of the Company, with respect to outstanding Securities of a series,
to maintain an office or agency in the places and for the purposes specified in
the Indenture for such series; or (vi) modify any of the foregoing provisions or
the provisions for the waiver of certain covenants and defaults, except to
increase any applicable percentage of the aggregate principal amount of
outstanding Securities the consent of the holders of which is required or to
provide with respect to any particular series the right to condition the
effectiveness of any supplemental indenture as to that series on the consent of
the holders of a specified percentage of the aggregate principal amount of
outstanding Securities of such series or to provide that certain other
provisions of the Indenture cannot be modified or waived without the consent of
the holder of each outstanding Security affected thereby. It is also provided in
the Indenture that the holders of a majority in aggregate principal amount of
the Securities of a series at the time outstanding may on behalf of the holders
of all the Securities of such series waive any past default under 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, if any, on any
Security

                                       2
<Page>
of such series or in respect of a covenant or provision which cannot be modified
without the consent of the Holder of each outstanding Security of the series
affected. Any such consent or waiver by the holder of this Note shall be
conclusive and binding upon such holder and upon all future holders and owners
of this Note and any Notes which may be issued in exchange or substitution
herefor, irrespective of whether or not any notation thereof is made upon this
Note or such other Notes.

    No reference herein to the Indenture and no provision of this Master Note or
of the Indenture shall alter or impair the obligation of the Company, which is
absolute and unconditional, to pay the principal of, if any, and interest on
this Note at the place, at the respective times, at the rate and in the coin or
currency herein prescribed.

    The Indenture permits the Company to Discharge its obligations with respect
to the Securities on the 91st day following the satisfaction of the conditions
set forth in the Indenture, which include the deposit with the Trustee of money
or U.S. Government Obligations or a combination thereof sufficient to pay and
discharge each installment of principal of (including premium, if any, on) and
interest, if any, on the outstanding Securities.

    If the Company shall, in accordance with Section 901 of the Indenture,
consolidate with or merge into any other corporation or convey or transfer its
properties and assets substantially as an entirety to any Person, the successor
shall succeed to, and be substituted for, the Person named as the "Company" on
the face of this Note, all on the terms set forth in the Indenture.

    Unless otherwise specified in a pricing supplement, beneficial interest in
Securities subject to this Master Note are issuable in registered form without
coupons in denominations of $1,000.00 and any integral multiple of $1,000.00. In
the manner and subject to the limitations provided in the Indenture, but without
the payment of any service charge, Notes may be exchanged for an equal aggregate
principal amount of Notes of other authorized denominations at the office or
agency of the Company maintained for such purpose in the Borough of Manhattan,
The City and State of New York.

    No recourse for the payment of the principal of, premium, if any, or
interest on this Master Note, or for any claim based hereon or otherwise in
respect hereof, and no recourse under or upon any obligation, covenant or
agreement of the Company in the Indenture or any indenture supplemental thereto
or in any Note, or because of the creation of any indebtedness represented
thereby, shall be had against any incorporator, stockholder, officer or
director, as such, past, present or future, of the Company or of any successor
corporation, either directly or through the Company or any successor
corporation, whether by virtue of any constitution, statute or rule of law or by
the enforcement of any assessment or penalty or otherwise, all such liability
being, by the acceptance hereof and as part of the consideration for the issue
hereof, expressly waived and released.

    Unless otherwise defined in this Master Note, all terms used in this Master
Note which are defined in the Indenture shall have the meanings assigned to them
in the Indenture.

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

                          [END OF REVERSE OF MASTER NOTE]

                                       3

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