<PAGE>

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

                    PREFERRED SECURITIES GUARANTEE AGREEMENT

                          UNISYS CAPITAL TRUST [I] [II]

                           Dated as of _______________

                      ====================================
<PAGE>
                                TABLE OF CONTENTS

<TABLE>
<S>                                                                                 <C>
ARTICLE I  DEFINITIONS AND INTERPRETATION.........................................   1

SECTION 1.1     DEFINITIONS AND INTERPRETATION....................................   1

ARTICLE II  TRUST INDENTURE.......................................................   4

SECTION 2.1     TRUST INDENTURE ACT; APPLICATION..................................   4
SECTION 2.2     LISTS OF HOLDERS OF SECURITIES....................................   4
SECTION 2.3     REPORTS BY THE PREFERRED GUARANTEE TRUSTEE........................   5
SECTION 2.4     PERIODIC REPORTS TO PREFERRED GUARANTEE TRUSTEE...................   5
SECTION 2.5     EVIDENCE OF COMPLIANCE WITH CONDITIONS PRECEDENT..................   5
SECTION 2.6     EVENTS OF DEFAULT; WAIVER.........................................   5
SECTION 2.7     EVENT OF DEFAULT; NOTICE..........................................   6
SECTION 2.8     CONFLICTING INTERESTS.............................................   6

ARTICLE III  POWERS, DUTIES AND RIGHTS OF PREFERRED GUARANTEE TRUSTEE.............   6

SECTION 3.1     POWERS AND DUTIES OF THE PREFERRED GUARANTEE TRUSTEE..............   6
SECTION 3.2     CERTAIN RIGHTS OF PREFERRED GUARANTEE TRUSTEE.....................   8
SECTION 3.3     NOT RESPONSIBLE FOR RECITALS OR ISSUANCE OF PREFERRED SECURITIES
                GUARANTEE.........................................................   9

ARTICLE IV  PREFERRED GUARANTEE TRUSTEE...........................................  10

SECTION 4.1     PREFERRED GUARANTEE TRUSTEE; ELIGIBILITY..........................  10
SECTION 4.2     APPOINTMENT, REMOVAL AND RESIGNATION OF PREFERRED GUARANTEE
                TRUSTEE...........................................................  10

ARTICLE V  GUARANTEE..............................................................  11

SECTION 5.1     GUARANTEE.........................................................  11
SECTION 5.2     WAIVER OF NOTICE AND DEMAND.......................................  11
SECTION 5.3     OBLIGATIONS NOT AFFECTED..........................................  11
SECTION 5.4     RIGHTS OF HOLDERS.................................................  12
</TABLE>
<PAGE>
<TABLE>
<S>                                                                                 <C>
SECTION 5.5     GUARANTEE OF PAYMENT..............................................  13
SECTION 5.6     SUBROGATION.......................................................  13
SECTION 5.7     INDEPENDENT OBLIGATIONS...........................................  13

ARTICLE VI  LIMITATION OF TRANSACTIONS; SUBORDINATION.............................  13

SECTION 6.1     LIMITATION OF TRANSACTIONS........................................  13
SECTION 6.2     RANKING...........................................................  14

ARTICLE VII  TERMINATION..........................................................  14

SECTION 7.1     TERMINATION.......................................................  14

ARTICLE VIII  INDEMNIFICATION.....................................................  14

SECTION 8.1     EXCULPATION.......................................................  14
SECTION 8.2     INDEMNIFICATION...................................................  15

ARTICLE IX  MISCELLANEOUS.........................................................  15

SECTION 9.1     SUCCESSORS AND ASSIGNS............................................  15
SECTION 9.2     AMENDMENTS........................................................  15
SECTION 9.3     NOTICES...........................................................  15
SECTION 9.4     BENEFIT...........................................................  16
SECTION 9.5     GOVERNING LAW.....................................................  16
</TABLE>
<PAGE>
                    PREFERRED SECURITIES GUARANTEE AGREEMENT

            This GUARANTEE AGREEMENT (the "Preferred Securities Guarantee"),
dated as of ____________, is executed and delivered by Unisys Corporation, a
Delaware corporation (the "Guarantor"), and HSBC Bank USA, a New York banking
corporation, as trustee (the "Preferred Guarantee Trustee"), for the benefit of
the Holders (as defined herein) from time to time of the Preferred Securities
(as defined herein) of Unisys Capital Trust [I] [II], a Delaware statutory
business trust (the "Issuer").

            WHEREAS, pursuant to an Amended and Restated Declaration of Trust
(the "Declaration"), dated as of ____________, among the trustees of the Issuer
named therein, the Guarantor, as sponsor, and the holders from time to time of
undivided beneficial interests in the assets of the Issuer, the Issuer is
issuing on the date hereof [ ] preferred securities, having an aggregate
liquidation amount of $[ ] (plus up to an additional [ ] preferred securities,
having an aggregate liquidation amount of $[ ], to cover over-allotments),
designated the _____% Trust Originated Preferred Securities (the "Preferred
Securities");

            WHEREAS, as incentive for the Holders to purchase the Preferred
Securities, the Guarantor desires irrevocably and unconditionally to agree, to
the extent set forth in this Preferred Securities Guarantee, to pay to the
Holders of the Preferred Securities the Guarantee Payments (as defined herein)
and to make certain other payments on the terms and conditions set forth herein.

            WHEREAS, the Guarantor is also executing and delivering a guarantee
agreement (the "Common Securities Guarantee") in substantially identical terms
to this Preferred Securities Guarantee for the benefit of the holders of the
Common Securities (as defined herein), except that if an Event of Default (as
defined in the Indenture), has occurred and is continuing, the rights of holders
of the Common Securities to receive payments under the Common Securities
Guarantee are subordinated to the rights of Holders of Preferred Securities to
receive Guarantee Payments under this Preferred Securities Guarantee.

            NOW, THEREFORE, in consideration of the purchase by each Holder of
Preferred Securities, which purchase the Guarantor hereby agrees shall benefit
the Guarantor, the Guarantor executes and delivers this Preferred Securities
Guarantee for the benefit of the Holders.

                                    ARTICLE I
                         DEFINITIONS AND INTERPRETATION

SECTION 1.1 Definitions and Interpretation

            In this Preferred Securities Guarantee, unless the context otherwise
requires:

      (a) Capitalized terms used in this Preferred Securities Guarantee but not
defined in the preamble above have the respective meanings assigned to them in
this Section 1.1;

      (b) a term defined anywhere in this Preferred Securities Guarantee has the
same meaning throughout;


                                       1
<PAGE>
      (c) all references to "the Preferred Securities Guarantee" or "this
Preferred Securities Guarantee" are to this Preferred Securities Guarantee as
modified, supplemented or amended from time to time;

      (d) all references in this Preferred Securities Guarantee to Articles and
Sections are to Articles and Sections of this Preferred Securities Guarantee,
unless otherwise specified;

      (e) a term defined in the Trust Indenture Act has the same meaning when
used in this Preferred Securities Guarantee, unless otherwise defined in this
Preferred Securities Guarantee or unless the context otherwise requires; and

      (f) a reference to the singular includes the plural and vice versa.

            "Affiliate" has the same meaning as given to that term in Rule 405
of the Securities Act of 1933, as amended, or any successor rule thereunder.

            "Business Day" means any day other than a day on which banking
institutions in the City of New York, New York are authorized or required by any
applicable law to close.

            "Common Securities" means the securities representing common
undivided beneficial interests in the assets of the Issuer.

            "Corporate Trust Office" means the office of the Preferred Guarantee
Trustee at which the corporate trust business of the Preferred Guarantee Trustee
shall, at any particular time, be principally administered, which office at the
date of execution of this Preferred Securities Guarantee is located at 452 Fifth
Avenue, New York, New York 10018.

            "Covered Person" means any Holder or beneficial owner of Preferred
Securities.

            "Debentures" means the series of junior subordinated debt securities
of the Guarantor designated the ___% [Junior Subordinated Deferrable Interest
Debentures] due [ ] held by the Institutional Trustee (as defined in the
Declaration) of the Issuer.

            "Distribution" means a distribution payable to Holders of Preferred
Securities in accordance with Section 6.1 of the Declaration.

            "Event of Default" means a default by the Guarantor on any of its
payment or other obligations under this Preferred Securities Guarantee.

            "Guarantee Payments" means the following payments or distributions,
without duplication, with respect to the Preferred Securities, to the extent not
paid or made by the Issuer: (i) any accrued and unpaid Distributions (as defined
in the Declaration) that are required to be paid on such Preferred Securities to
the extent the Issuer shall have funds available therefor, (ii) the redemption
price, including all accrued and unpaid Distributions to the date of redemption
(the "Redemption Price") to the extent the Issuer has funds available therefor,
with respect to any Preferred Securities called for redemption by the Issuer,
and (iii) upon a voluntary or involuntary dissolution, winding-up or termination
of the Issuer (other than


                                       2
<PAGE>
in connection with the distribution of Debentures to the Holders in exchange for
Preferred Securities as provided in the Declaration), the lesser of (a) the
aggregate of the liquidation amount and all accrued and unpaid Distributions on
the Preferred Securities to the date of payment, to the extent the Issuer shall
have funds available therefor, and (b) the amount of assets of the Issuer
remaining available for distribution to Holders in liquidation of the Issuer (in
either case, the "Liquidation Distribution"). If an event of default under the
Indenture has occurred and is continuing, the rights of holders of the Common
Securities to receive payments under the Common Securities Guarantee Agreement
are subordinated to the rights of Holders of Preferred Securities to receive
Guarantee Payments.

            "Holder" shall mean any holder, as registered on the books and
records of the Issuer of any Preferred Securities; provided, however, that, in
determining whether the holders of the requisite percentage of Preferred
Securities have given any request, notice, consent or waiver hereunder, "Holder"
shall not include the Guarantor or any Affiliate of the Guarantor.

            "Indemnified Person" means the Preferred Guarantee Trustee, any
Affiliate of the Preferred Guarantee Trustee, or any officers, directors,
shareholders, members, partners, employees, representatives, nominees,
custodians or agents of the Preferred Guarantee Trustee.

            "Indenture" means the Indenture dated as of ______________, between
the Guarantor (the "Debenture Issuer") and HSBC Bank USA, as trustee, and any
indenture supplemental thereto pursuant to which certain subordinated debt
securities of the Debenture Issuer are to be issued to the Institutional Trustee
of the Issuer.

            "Majority in liquidation amount of Preferred Securities" means,
except as provided by the Trust Indenture Act, a vote by Holder(s) of Preferred
Securities, voting separately as a class, of more than 50% of the liquidation
amount (including the stated amount that would be paid on redemption,
liquidation or otherwise, plus accrued and unpaid Distributions to the date upon
which the voting percentages are determined) of all Preferred Securities.

            "Officers' Certificate" means, with respect to any Person, a
certificate signed by two Authorized Officers of such Person. Any Officers'
Certificate delivered with respect to compliance with a condition or covenant
provided for in this Preferred Securities Guarantee shall include:

      (a) a statement that each officer signing the Officers' Certificate has
read the covenant or condition and the definition relating thereto;

      (b) a brief statement of the nature and scope of the examination or
investigation undertaken by each officer in rendering the Officers' Certificate;

      (c) a statement that each such officer has made such examination or
investigation as, in such officer's opinion, is necessary to enable such officer
to express an informed opinion as to whether or not such covenant or condition
has been complied with; and

      (d) a statement as to whether, in the opinion of each such officer, such
condition or covenant has been complied with.


                                       3
<PAGE>
            "Person" means a legal person, including any individual,
corporation, estate, partnership, joint venture, association, joint stock
company, limited liability company, trust, unincorporated association, or
government or any agency or political subdivision thereof, or any other entity
of whatever nature.

            "Preferred Guarantee Trustee" means HSBC Bank USA, a New York
banking corporation, until a Successor Preferred Guarantee Trustee has been
appointed and has accepted such appointment pursuant to the terms of this
Preferred Securities Guarantee and thereafter means each such Successor
Preferred Guarantee Trustee.

            "Responsible Officer" means, with respect to the Preferred Guarantee
Trustee, any officer within the Corporate Trust Office of the Preferred
Guarantee Trustee with direct responsibility for the administration of this
Preferred Securities Guarantee and also means, with respect to a particular
corporate trust matter, any other officer to whom such matter is referred
because of that officer's knowledge of and familiarity with the particular
subject.

            "Successor Preferred Guarantee Trustee" means a successor Preferred
Guarantee Trustee possessing the qualifications to act as Preferred Guarantee
Trustee under Section 4.1.

            "Trust Indenture Act" means the Trust Indenture Act of 1939, as
amended.

            "Trust Securities" means the Common Securities and the Preferred
Securities.

                                   ARTICLE II
                               TRUST INDENTURE ACT

SECTION 2.1 Trust Indenture Act; Application

      (a) This Preferred Securities Guarantee is subject to the provisions of
the Trust Indenture Act that are required to be part of this Preferred
Securities Guarantee and shall, to the extent applicable, be governed by such
provisions; and

      (b) if and to the extent that any provision of this Preferred Securities
Guarantee limits, qualifies or conflicts with the duties imposed by Section 310
to 317, inclusive, of the Trust Indenture Act, such imposed duties shall
control.

SECTION 2.2 Lists of Holders of Securities

      (a) The Guarantor shall provide the Preferred Guarantee Trustee with a
list, in such form as the Preferred Guarantee Trustee may reasonably require, of
the names and addresses of the Holders of the Preferred Securities ("List of
Holders") as of such date, (i) within 15 days after each record date for payment
of Distributions, and (ii) at any other time within 30 days of receipt by the
Guarantor of a written request for a List of Holders as of a date no more than
15 days before such List of Holders is given to the Preferred Guarantee Trustee
provided, that the Guarantor shall not be obligated to provide such List of
Holders at any time the List of Holders does not differ from the most recent
List of


                                       4
<PAGE>
Holders given to the Preferred Guarantee Trustee by the Guarantor. The Preferred
Guarantee Trustee may destroy any List of Holders previously given to it on
receipt of a new List of Holders.

      (b) The Preferred Guarantee Trustee shall comply with its obligations
under Sections 311(a), 311(b) and Section 312(b) of the Trust Indenture Act.

SECTION 2.3 Reports by the Preferred Guarantee Trustee

      Within 60 days after May 15 of each year, the Preferred Guarantee Trustee
shall provide to the Holders of the Preferred Securities such reports as are
required by Section 313 of the Trust Indenture Act, if any, in the form and in
the manner provided by Section 313 of the Trust Indenture Act. The Preferred
Guarantee Trustee shall also comply with the requirements of Section 313(d) of
the Trust Indenture Act.

SECTION 2.4 Periodic Reports to Preferred Guarantee Trustee

            The Guarantor shall provide to the Preferred Guarantee Trustee such
documents, reports and information if any as required by Section 314 of the
Trust Indenture Act and the compliance certificate required by Section 314 of
the Trust Indenture Act in the form, in the manner and at the times required by
Section 314 of the Trust Indenture Act.

SECTION 2.5 Evidence of Compliance with Conditions Precedent

            The Guarantor shall provide to the Preferred Guarantee Trustee such
evidence of compliance with any conditions precedent, if any, provided for in
this Preferred Securities Guarantee that relate to any of the matters set forth
in Section 314(c) of the Trust Indenture Act. Any certificate or opinion
required to be given by an officer pursuant to Section 314(c)(1) may be given in
the form of an Officers' Certificate.

SECTION 2.6 Events of Default; Waiver

            The Holders of a Majority in liquidation amount of Preferred
Securities may, by vote, on behalf of the Holders of all of the Preferred
Securities, waive any past Event of Default and its consequences. Upon such
waiver, any such Event of Default shall cease to exist, and any Event of Default
arising therefrom shall be deemed to have been cured, for every purpose of this
Preferred Securities Guarantee, but no such waiver shall extend to any
subsequent or other default or Event of Default or impair any right consequent
thereon.

SECTION 2.7 Event of Default; Notice

      (a) The Preferred Guarantee Trustee shall, within 90 days after the
occurrence of an Event of Default, transmit by mail, first class postage
prepaid, to the Holders of the Preferred Securities, notices of all Events of
Default actually known to a Responsible Officer of the Preferred Guarantee
Trustee, unless such defaults have been cured before the giving of such notice,
provided, that, the Preferred Guarantee Trustee shall be protected in
withholding such notice if and so long as a Responsible Officer of the Preferred
Guarantee Trustee in good faith determines that the withholding of such notice
is in the interests of the Holders of the Preferred Securities.


                                       5
<PAGE>
      (b) The Preferred Guarantee Trustee shall not be deemed to have knowledge
of any Event of Default unless the Preferred Guarantee Trustee shall have
received written notice, or a Responsible Officer of the Preferred Guarantee
Trustee charged with the administration of this Preferred Securities Guarantee
shall have obtained actual knowledge, of such Event of Default.

SECTION 2.8 Conflicting Interests

            The Declaration shall be deemed to be specifically described in this
Preferred Securities Guarantee for the purposes of clause (i) of the first
proviso contained in Section 310(b) of the Trust Indenture Act.

                                   ARTICLE III
                          POWERS, DUTIES AND RIGHTS OF
                           PREFERRED GUARANTEE TRUSTEE

SECTION 3.1 Powers and Duties of the Preferred Guarantee Trustee

      (a) This Preferred Securities Guarantee shall be held by the Preferred
Guarantee Trustee for the benefit of the Holders of the Preferred Securities,
and the Preferred Guarantee Trustee shall not transfer this Preferred Securities
Guarantee to any Person except a Holder of Preferred Securities exercising his
or her rights pursuant to Section 5.4(b) or to a Successor Preferred Guarantee
Trustee on acceptance by such Successor Preferred Guarantee Trustee of its
appointment to act as Successor Preferred Guarantee Trustee. The right, title
and interest of the Preferred Guarantee Trustee shall automatically vest in any
Successor Preferred Guarantee Trustee, and such vesting and cessation of title
shall be effective whether or not conveyancing documents have been executed and
delivered pursuant to the appointment of such Successor Preferred Guarantee
Trustee.

      (b) If an Event of Default actually known to a Responsible Officer of the
Preferred Guarantee Trustee has occurred and is continuing, the Preferred
Guarantee Trustee shall enforce this Preferred Securities Guarantee for the
benefit of the Holders of the Preferred Securities.

      (c) The Preferred Guarantee Trustee, before the occurrence of any Event of
Default and after the curing of all Events of Default that may have occurred,
shall undertake to perform only such duties as are specifically set forth in
this Preferred Securities Guarantee, and no implied covenants shall be read into
this Preferred Securities Guarantee against the Preferred Guarantee Trustee. In
case an Event of Default has occurred (that has not been cured or waived
pursuant to Section 2.6) and is actually known to a Responsible Officer of the
Preferred Guarantee Trustee, the Preferred Guarantee Trustee shall exercise such
of the rights and powers vested in it by this Preferred Securities Guarantee,
and use the same degree of care and skill in its exercise thereof, as a prudent
person would exercise or use under the circumstances in the conduct of his or
her own affairs.

      (d) No provision of this Preferred Securities Guarantee shall be construed
to relieve the Preferred Guarantee Trustee from liability for its own negligent
action, its own negligent failure to act, or its own willful misconduct, except
that:

      (i) prior to the occurrence of any Event of Default and after the curing
or waiving of all such Events of Default that may have occurred:


                                       6
<PAGE>
      (A) the duties and obligations of the Preferred Guarantee Trustee shall be
determined solely by the express provisions of this Preferred Securities
Guarantee, and the Preferred Guarantee Trustee shall not be liable except for
the performance of such duties and obligations as are specifically set forth in
this Preferred Securities Guarantee, and no implied covenants or obligations
shall be read into this Preferred Securities Guarantee against the Preferred
Guarantee Trustee; and

      (B) in the absence of bad faith on the part of the Preferred Guarantee
Trustee, the Preferred Guarantee Trustee may conclusively rely, as to the truth
of the statements and the correctness of the opinions expressed therein, upon
any certificates or opinions furnished to the Preferred Guarantee Trustee and
conforming to the requirements of this Preferred Securities Guarantee; but in
the case of any such certificates or opinions that by any provision hereof are
specifically required to be furnished to the Preferred Guarantee Trustee, the
Preferred Guarantee Trustee shall be under a duty to examine the same to
determine whether or not they conform to the requirements of this Preferred
Securities Guarantee;

      (ii) Preferred Guarantee Trustee shall not be liable for any error of
judgment made in good faith by a Responsible Officer of the Preferred Guarantee
Trustee, unless it shall be proved that the Preferred Guarantee Trustee was
negligent in ascertaining the pertinent facts upon which such judgment was made;

      (iii) the Preferred Guarantee Trustee shall not be liable with respect to
any action taken or omitted to be taken by it in good faith in accordance with
the direction of the Holders of not less than a Majority in liquidation amount
of the Preferred Securities relating to the time, method and place of conducting
any proceeding for any remedy available to the Preferred Guarantee Trustee, or
exercising any trust or power conferred upon the Preferred Guarantee Trustee
under this Preferred Securities Guarantee; and

      (iv) no provision of this Preferred Securities Guarantee shall require the
Preferred Guarantee Trustee to expend or risk its own funds or otherwise incur
personal financial liability in the performance of any of its duties or in the
exercise of any of its rights or powers, if the Preferred Guarantee Trustee
shall have reasonable grounds for believing that the repayment of such funds or
liability is not reasonably assured to it under the terms of this Preferred
Securities Guarantee or indemnity, reasonably satisfactory to the Preferred
Guarantee Trustee, against such risk or liability is not reasonably assured to
it.

SECTION 3.2 Certain Rights of Preferred Guarantee Trustee

      (a) Subject to the provisions of Section 3.1:

      (i) The Preferred Guarantee Trustee may conclusively rely, and shall be
fully protected in acting or refraining from acting upon, any resolution,
certificate, statement, instrument, opinion, report, notice, request, direction,
consent, order, bond, debenture, note, other evidence of indebtedness or other
paper or document believed by it to be genuine and to have been signed, sent or
presented by the proper party or parties.

      (ii) Any direction or act of the Guarantor contemplated by this Preferred
Securities Guarantee shall be sufficiently evidenced by an Officers'
Certificate.


                                       7
<PAGE>
      (iii) Whenever, in the administration of this Preferred Securities
Guarantee, the Preferred Guarantee Trustee shall deem it desirable that a matter
be proved or established before taking, suffering or omitting any action
hereunder, the Preferred Guarantee Trustee (unless other evidence is herein
specifically prescribed) may, in the absence of bad faith on its part, request
and conclusively rely upon an Officers' Certificate which, upon receipt of such
request, shall be promptly delivered by the Guarantor.

      (iv) The Preferred Guarantee Trustee shall have no duty to see to any
recording, filing or registration of any instrument (or any rerecording,
refiling or registration thereof).

      (v) The Preferred Guarantee Trustee may consult with counsel, and the
written advice or opinion of such counsel with respect to legal matters shall be
full and complete authorization and protection in respect of any action taken,
suffered or omitted by it hereunder in good faith and in accordance with such
advice or opinion. Such counsel may be counsel to the Guarantor or any of its
Affiliates and may include any of its employees. The Preferred Guarantee Trustee
shall have the right at any time to seek instructions concerning the
administration of this Preferred Securities Guarantee from any court of
competent jurisdiction.

      (vi) The Preferred Guarantee Trustee shall be under no obligation to
exercise any of the rights or powers vested in it by this Preferred Securities
Guarantee at the request or direction of any Holder, unless such Holder shall
have provided to the Preferred Guarantee Trustee such security and indemnity,
reasonably satisfactory to the Preferred Guarantee Trustee, against the costs,
expenses (including attorneys' fees and expenses and the expenses of the
Preferred Guarantee Trustee's agents, nominees or custodians) and liabilities
that might be incurred by it in complying with such request or direction,
including such reasonable advances as may be requested by the Preferred
Guarantee Trustee; provided that, nothing contained in this Section 3.2(a)(vi)
shall be taken to relieve the Preferred Guarantee Trustee, upon the occurrence
of an Event of Default, of its obligation to exercise the rights and powers
vested in it by this Preferred Securities Guarantee.

      (vii) The Preferred Guarantee Trustee shall not be bound to any
investigation into the facts or matters stated in any resolution, certificate,
statement, instrument, opinion, report, notice, request, direction, consent,
order, bond, debenture, note, other evidence of indebtedness or other paper or
document, but the Preferred Guarantee Trustee, in its discretion, may make such
further inquiry or investigation into such facts or matters as it may see fit.

      (viii) The Preferred Guarantee Trustee may execute any of the trusts or
powers hereunder or perform any duties hereunder either directly or by or
through agents, nominees, custodians or attorneys, and the Preferred Guarantee
Trustee shall not be responsible for any misconduct or negligence on the part of
any agent or attorney appointed with due care by it hereunder.

      (ix) Any action taken by the Preferred Guarantee Trustee or its agents
hereunder shall bind the Holders of the Preferred Securities, and the signature
of the Preferred Guarantee Trustee or its agents alone shall be sufficient and
effective to perform any such action. No third party shall be required to
inquire as to the authority of the Preferred Guarantee Trustee to so act or as
to its compliance with any of the terms and provisions of this


                                       8
<PAGE>
Preferred Securities Guarantee, both of which shall be conclusively evidenced by
the Preferred Guarantee Trustee's or its agent's taking such action.

      (x) Whenever in the administration of this Preferred Securities Guarantee
the Preferred Guarantee Trustee shall deem it desirable to receive instructions
with respect to enforcing any remedy or right or taking any other action
hereunder, the Preferred Guarantee Trustee (i) may request instructions from the
Holders of a Majority in liquidation amount of the Preferred Securities, (ii)
may refrain from enforcing such remedy or right or taking such other action
until such instructions are received, and (iii) shall be protected in
conclusively relying on or acting in accordance with such instructions.

      (b) No provision of this Preferred Securities Guarantee shall be deemed to
impose any duty or obligation on the Preferred Guarantee Trustee to perform any
act or acts or exercise any right, power, duty or obligation conferred or
imposed on it in any jurisdiction in which it shall be illegal, or in which the
Preferred Guarantee Trustee shall be unqualified or incompetent in accordance
with applicable law, to perform any such act or acts or to exercise any such
right, power, duty or obligation. No permissive power or authority available to
the Preferred Guarantee Trustee shall be construed to be a duty.

SECTION 3.3 Not Responsible for Recitals or Issuance of Preferred Securities
Guarantee

            The recitals contained in this Preferred Securities Guarantee shall
be taken as the statements of the Guarantor, and the Preferred Guarantee Trustee
does not assume any responsibility for their correctness. The Preferred
Guarantee Trustee makes no representation as to the validity or sufficiency of
this Preferred Securities Guarantee.

                                   ARTICLE IV
                           PREFERRED GUARANTEE TRUSTEE

SECTION 4.1 Preferred Guarantee Trustee; Eligibility

      (a) There shall at all times be a Preferred Guarantee Trustee which shall:

      (i) not be an Affiliate of the Guarantor; and

      (ii) be a corporation organized and doing business under the laws of the
United States of America or any State or Territory thereof or of the District of
Columbia, or a Person permitted by the Securities and Exchange Commission to act
as an institutional trustee under the Trust Indenture Act, authorized under such
laws to exercise corporate trust powers, having a combined capital and surplus
of at least 50 million U.S. dollars ($50,000,000), subject to supervision or
examination by Federal, State, Territorial or District of Columbia authority. If
such Person publishes reports of condition at least annually, pursuant to law or
to the requirements of the supervising or examining authority referred to above,
then, for the purposes of this Section 4.1(a)(ii), the combined capital and
surplus of such Person shall be deemed to be its combined capital and surplus as
set forth in its most recent report of condition so published.


                                       9
<PAGE>
      (b) If at any time the Preferred Guarantee Trustee shall cease to be
eligible to so act under Section 4.1(a), the Preferred Guarantee Trustee shall
immediately resign in the manner and with the effect set out in Section 4.2(c).

      (c) If the Preferred Guarantee Trustee has or shall acquire any
"conflicting interest" within the meaning of Section 310(b) of the Trust
Indenture Act, the Preferred Guarantee Trustee and Guarantor shall in all
respects comply with the provisions of Section 310(b) of the Trust Indenture
Act.

SECTION 4.2 Appointment, Removal and Resignation of Preferred Guarantee Trustee.

      (a) Subject to Section 4.2(b), the Preferred Guarantee Trustee may be
appointed or removed without cause at any time by the Guarantor.

      (b) The Preferred Guarantee Trustee shall not be removed in accordance
with Section 4.2(a) until a Successor Preferred Guarantee Trustee has been
appointed and has accepted such appointment by written instrument executed by
such Successor Preferred Guarantee Trustee and delivered to the Guarantor.

      (c) The Preferred Guarantee Trustee appointed to office shall hold office
until a Successor Preferred Guarantee Trustee shall have been appointed or until
its removal or resignation. The Preferred Guarantee Trustee may resign from
office (without need for prior or subsequent accounting) by an instrument in
writing executed by the Preferred Guarantee Trustee and delivered to the
Guarantor, which resignation shall not take effect until a Successor Preferred
Guarantee Trustee has been appointed and has accepted such appointment by
instrument in writing executed by such Successor Preferred Guarantee Trustee and
delivered to the Guarantor and the resigning Preferred Guarantee Trustee.

      (d) If no Successor Preferred Guarantee Trustee shall have been appointed
and accepted appointment as provided in this Section 4.2 within 60 days after
delivery to the Guarantor of an instrument of removal or resignation, the
resigning Preferred Guarantee Trustee may petition any court of competent
jurisdiction for appointment of a Successor Preferred Guarantee Trustee. Such
court may thereupon, after prescribing such notice, if any, as it may deem
proper, appoint a Successor Preferred Guarantee Trustee.

      (e) No Preferred Guarantee Trustee shall be liable for the acts or
omissions to act of any Successor Preferred Guarantee Trustee.

      (f) Upon termination of this Preferred Securities Guarantee or removal or
resignation of the Preferred Guarantee Trustee pursuant to this Section 4.2, the
Guarantor shall pay to the Preferred Guarantee Trustee all amounts accrued to
the date of such termination, removal or resignation.


                                       10
<PAGE>
                                    ARTICLE V
                                    GUARANTEE

SECTION 5.1 Guarantee

            The Guarantor irrevocably and unconditionally agrees to pay in full
to the Holders the Guarantee Payments (without duplication of amounts
theretofore paid by the Issuer), as and when due, regardless of any defense,
right of set-off or counterclaim that the Issuer may have or assert. The
Guarantor's obligation to make a Guarantee Payment may be satisfied by direct
payment of the required amounts by the Guarantor to the Holders or by causing
the Issuer to pay such amounts to the Holders.

SECTION 5.2 Waiver of Notice and Demand

            The Guarantor hereby waives notice of acceptance of this Preferred
Securities Guarantee and of any liability to which it applies or may apply,
presentment, demand for payment, any right to require a proceeding first against
the Issuer or any other Person before proceeding against the Guarantor, protest,
notice of nonpayment, notice of dishonor, notice of redemption and all other
notices and demands.

SECTION 5.3 Obligations Not Affected

            The obligations, covenants, agreements and duties of the Guarantor
under this Preferred Securities Guarantee shall in no way be affected or
impaired by reason of the happening from time to time of any of the following:

      (a) the release or waiver, by operation of law or otherwise, of the
performance or observance by the Issuer of any express or implied agreement,
covenant, term or condition relating to the Preferred Securities to be performed
or observed by the Issuer;

      (b) the extension of time for the payment by the Issuer of all or any
portion of the Distributions, Redemption Price, Liquidation Distribution or any
other sums payable under the terms of the Preferred Securities or the extension
of time for the performance of any other obligation under, arising out of, or in
connection with, the Preferred Securities (other than an extension of time for
payment of Distributions, Redemption Price, Liquidation Distribution or other
sum payable that results from the extension of any interest payment period on
the Debentures or any extension of the maturity date of the Debentures permitted
by the Indenture);

      (c) any failure, omission, delay or lack of diligence on the part of the
Holders to enforce, assert or exercise any right, privilege, power or remedy
conferred on the Holders pursuant to the terms of the Preferred Securities, or
any action on the part of the Issuer granting indulgence or extension of any
kind;

      (d) the voluntary or involuntary liquidation, dissolution, sale of any
collateral, receivership, insolvency, bankruptcy, assignment for the benefit of
creditors, reorganization, arrangement, composition or readjustment of debt of,
or other similar proceedings affecting, the Issuer or any of the assets of the
Issuer;


                                       11
<PAGE>
      (e) any invalidity of, or defect or deficiency in, the Preferred
Securities;

      (f) the settlement or compromise of any obligation guaranteed hereby or
hereby incurred; or

      (g) any other circumstance whatsoever that might otherwise constitute a
legal or equitable discharge or defense of a guarantor, it being the intent of
this Section 5.3 that the obligations of the Guarantor hereunder shall be
absolute and unconditional under any and all circumstances.

            There shall be no obligation of the Holders to give notice to, or
obtain consent of, the Guarantor with respect to the happening of any of the
foregoing.

SECTION 5.4 Rights of Holders

      (a) The Holders of a Majority in liquidation amount of the Preferred
Securities have the right to direct the time, method and place of conducting of
any proceeding for any remedy available to the Preferred Guarantee Trustee in
respect of this Preferred Securities Guarantee or exercising any trust or power
conferred upon the Preferred Guarantee Trustee under this Preferred Securities
Guarantee.

      (b) If the Preferred Guarantee Trustee fails to enforce such Preferred
Securities Guarantee, any Holder of Preferred Securities may institute a legal
proceeding directly against the Guarantor to enforce the Preferred Guarantee
Trustee's rights under this Preferred Securities Guarantee, without first
instituting a legal proceeding against the Issuer, the Preferred Guarantee
Trustee or any other Person. The Guarantor waives any right or remedy to require
that any action be brought first against the Issuer or any other Person before
proceeding directly against the Guarantor.

SECTION 5.5 Guarantee of Payment

            This Preferred Securities Guarantee creates a guarantee of payment
and not of collection.

SECTION 5.6 Subrogation

            The Guarantor shall be subrogated to all (if any) rights of the
Holders of Preferred Securities against the Issuer in respect of any amounts
paid to such Holders by the Guarantor under this Preferred Securities Guarantee;
provided, however, that the Guarantor shall not (except to the extent required
by mandatory provisions of law) be entitled to enforce or exercise any right
that it may acquire by way of subrogation or any indemnity, reimbursement or
other agreement, in all cases as a result of payment under this Preferred
Securities Guarantee, if, at the time of any such payment, any amounts are due
and unpaid under this Preferred Securities Guarantee. If any amount shall be
paid to the Guarantor in violation of the preceding sentence, the Guarantor
agrees to hold such amount in trust for the Holders and to pay over such amount
to the Holders.


                                       12
<PAGE>
SECTION 5.7 Independent Obligations

            The Guarantor acknowledges that its obligations hereunder are
independent of the obligations of the Issuer with respect to the Preferred
Securities, and that the Guarantor shall be liable as principal and as debtor
hereunder to make Guarantee Payments pursuant to the terms of this Preferred
Securities Guarantee notwithstanding the occurrence of any event referred to in
subsections (a) through (g), inclusive, of Section 5.3 hereof.

                                   ARTICLE VI
                    LIMITATION OF TRANSACTIONS; SUBORDINATION

SECTION 6.1 Limitation of Transactions

            So long as any Preferred Securities remain outstanding, if there
shall have occurred an Event of Default or an event of default under the
Declaration, then (a) the Guarantor shall not declare or pay any dividend on,
make any distributions with respect to, or redeem, purchase, acquire or make a
liquidation payment with respect to, any of its capital stock (other than (i)
purchases or acquisitions of shares of Common Stock in connection with the
satisfaction by the Guarantor of its obligations under any employee benefit
plans, (ii) as a result of a reclassification of the Guarantor's capital stock
or the exchange or conversion of one class or series of the Guarantor's capital
stock for another class or series of the Guarantor's capital stock or, (iii) the
purchase of fractional interests in shares of the Guarantor's capital stock
pursuant to the conversion or exchange provisions of such capital stock of the
Guarantor or the security being converted or exchanged) or make any guarantee
payments with respect to the foregoing or (b) the Guarantor shall not make any
payment of interest, principal or premium, if any, on or repay, repurchase or
redeem any debt securities (including guarantees) issued by the Guarantor which
rank pari passu with or junior to the Debentures.

SECTION 6.2 Ranking

            This Preferred Securities Guarantee will constitute an unsecured
obligation of the Guarantor and will rank (i) subordinate and junior in right of
payment to all other liabilities of the Guarantor, (ii) pari passu with the most
senior preferred or preference stock now or hereafter issued by the Guarantor
and with any guarantee now or hereafter entered into by the Guarantor in respect
of any preferred or preference stock of any Affiliate of the Guarantor, and
(iii) senior to the Guarantor's common stock.

                                   ARTICLE VII
                                   TERMINATION

SECTION 7.1 Termination

            This Preferred Securities Guarantee shall terminate upon (i) full
payment of the Redemption Price of all Preferred Securities, (ii) upon the
distribution of the Debentures to the Holders of all of the Preferred Securities
or (iii) upon full payment of the amounts payable in accordance with the
Declaration upon liquidation of the Issuer. Notwithstanding the foregoing, this
Preferred Securities Guarantee will continue to be effective or will be
reinstated, as the case may be, if at any time any Holder of


                                       13
<PAGE>
Preferred Securities must restore payment of any sums paid under the Preferred
Securities or under this Preferred Securities Guarantee.

                                  ARTICLE VIII
                                 INDEMNIFICATION

SECTION 8.1 Exculpation

      (a) No Indemnified Person shall be liable, responsible or accountable in
damages or otherwise to the Guarantor or any Covered Person for any loss, damage
or claim incurred by reason of any act or omission performed or omitted by such
Indemnified Person in good faith in accordance with this Preferred Securities
Guarantee and in a manner that such Indemnified Person reasonably believed to be
within the scope of the authority conferred on such Indemnified Person by this
Preferred Securities Guarantee or by law, except that an Indemnified Person
shall be liable for any such loss, damage or claim incurred by reason of such
Indemnified Person's negligence or willful misconduct with respect to such acts
or omissions.

      (b) An Indemnified Person shall be fully protected in relying in good
faith upon the records of the Guarantor and upon such information, opinions,
reports or statements presented to the Guarantor by any Person as to matters the
Indemnified Person reasonably believes are within such other Person's
professional or expert competence and who has been selected with reasonable care
by or on behalf of the Guarantor, including information, opinions, reports or
statements as to the value and amount of the assets, liabilities, profits,
losses, or any other facts pertinent to the existence and amount of assets from
which Distributions to Holders of Preferred Securities might properly be paid.

SECTION 8.2 Indemnification

            The Guarantor agrees to indemnify each Indemnified Person for, and
to hold each Indemnified Person harmless against, any loss, liability or expense
incurred without negligence or bad faith on its part, arising out of or in
connection with the acceptance or administration of the trust or trusts
hereunder, including the costs and expenses (including reasonable legal fees and
expenses) of defending itself against, or investigating, any claim or liability
in connection with the exercise or performance of any of its powers or duties
hereunder. The obligation to indemnify as set forth in this Section 8.2 shall
survive the resignation or removal of the Preferred Guarantee Trustee and the
termination of this Preferred Securities Guarantee.

                                   ARTICLE IX
                                  MISCELLANEOUS

SECTION 9.1 Successors and Assigns

            All guarantees and agreements contained in this Preferred Securities
Guarantee shall bind the successors, assigns, receivers, trustees and
representatives of the Guarantor and shall inure to the benefit of the Holders
of the Preferred Securities then outstanding.


                                       14
<PAGE>
SECTION 9.2 Amendments

            Except with respect to any changes that do not adversely affect the
rights of Holders (in which case no consent of Holders will be required), this
Preferred Securities Guarantee may only be amended with the prior approval of
the Holders of at least a Majority in liquidation amount of Preferred
Securities. The provisions of Section 12.2 of the Declaration with respect to
meetings of Holders of the Securities apply to the giving of such approval.

SECTION 9.3 Notices

            All notices provided for in this Preferred Securities Guarantee
shall be in writing, duly signed by the party giving such notice, and shall be
delivered, telecopied or mailed by registered or certified mail, as follows:

      (a) If given to the Preferred Guarantee Trustee, at the Preferred
Guarantee Trustee's mailing address set forth below (or such other address as
the Preferred Guarantee Trustee may give notice of to the Holders of the
Preferred Securities):

                                HSBC Bank USA
                                452 Fifth Avenue
                                New York, New York 10018
                                Attention: Issuer Services

      (b) If given to the Guarantor, at the Guarantor's mailing address set
forth below (or such other address as the Guarantor may give notice of to the
Preferred Guarantee Trustee and the Holders of the Preferred Securities):

                                Unisys Corporation
                                Unisys Way
                                Blue Bell, PA 19424

      (c) If given to any Holder of Preferred Securities, at the address set
forth on the books and records of the Issuer.

            All such notices shall be deemed to have been given when received in
person, telecopied with receipt confirmed, or mailed by first class mail,
postage prepaid except that if a notice or other document is refused delivery or
cannot be delivered because of a changed address of which no notice was given,
such notice or other document shall be deemed to have been delivered on the date
of such refusal or inability to deliver.

SECTION 9.4 Benefit

            This Preferred Securities Guarantee is solely for the benefit of the
Holders of the Preferred Securities and, subject to Section 3.1(a), is not
separately transferable from the Preferred Securities.


                                       15
<PAGE>
SECTION 9.5 Governing Law

            THIS PREFERRED SECURITIES GUARANTEE SHALL BE GOVERNED BY, AND
CONSTRUED AND INTERPRETED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

            THIS PREFERRED SECURITIES GUARANTEE is executed as of the day and
year first above written.


UNISYS CORPORATION, as Guarantor


By:_______________________________________
Name:
Title:


HSBC BANK USA, as Preferred
Guarantee Trustee


By:_______________________________________
Name:


                                       16