<PAGE>



                                                                 Exhibit 4.5

                                                                  EXECUTION COPY

                      PLATINUM UNDERWRITERS HOLDINGS, LTD.

                      STATE STREET BANK AND TRUST COMPANY

                      AS COLLATERAL AGENT, CUSTODIAL AGENT

                          AND SECURITIES INTERMEDIARY

                                      AND

                              JPMORGAN CHASE BANK

                           AS PURCHASE CONTRACT AGENT

                                PLEDGE AGREEMENT

                          DATED AS OF NOVEMBER 1,2002

<PAGE>

                                TABLE OF CONTENTS

<TABLE>
<S>                                                                                 <C>
                                        ARTICLE I
                                       DEFINITIONS

SECTION 1.1    Definitions ...................................................        2

                                       ARTICLE II
                             PLEDGE; CONTROL AND PERFECTION

SECTION 2.1    The Pledge ....................................................        4
SECTION 2.2    Control and Perfection ........................................        6

                                       ARTICLE III
                                 PAYMENTS ON COLLATERAL

SECTION 3.1    Payments ......................................................        8
SECTION 3.2    Application of Payments .......................................        9

                                       ARTICLE IV
                 SUBSTITUTION, RELEASE, REPLEDGE AND SETTLEMENT OF NOTES

SECTION 4.1    Collateral Substitution and the Creation of Stripped Units ....       10
SECTION 4.2    Collateral Substitution and the Re-Creation of Normal Units ...       10
SECTION 4.3    Termination Event .............................................       11
SECTION 4.4    Early Settlement; Merger Early Settlement; Cash Settlement ....       12
SECTION 4.5    Remarketing; Application of Proceeds; Settlement ..............       12

                                        ARTICLE V
                                 VOTING RIGHTS -- NOTES

SECTION 5.1    Exercise by Purchase Contract Agent ...........................       15

                                       ARTICLE VI
                        RIGHTS AND REMEDIES; TAX EVENT REDEMPTION

SECTION 6.1    Rights and Remedies of the Collateral Agent ...................       15
SECTION 6.2    Substitutions .................................................       17
SECTION 6.3    Tax Event Redemption ..........................................       17
SECTION 6.4    Prepayment of Notes ...........................................       17

                                       ARTICLE VII
                        REPRESENTATIONS AND WARRANTIES; COVENANTS

SECTION 7.1    Representations and Warranties of the Holders .................       18
</TABLE>

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<TABLE>
<S>                                                                                 <C>
SECTION 7.2    Representations and Warranties of the Collateral Agent,
               Custodial Agent and Securities Intermediary ...................       18
SECTION 7.3    Covenants .....................................................       19

                                      ARTICLE VIII
                                  THE COLLATERAL AGENT

SECTION 8.1    Appointment, Powers and Immunities ............................       20
SECTION 8.2    Instructions of the Company ...................................       21
SECTION 8.3    Reliance ......................................................       21
SECTION 8.4    Rights in Other Capacities ....................................       22
SECTION 8.5    Non-Reliance on Collateral Agent ..............................       22
SECTION 8.6    Compensation and Indemnity ....................................       22
SECTION 8.7    Failure to Act ................................................       23
SECTION 8.8    Resignation ...................................................       24
SECTION 8.9    Right to Appoint Agent or Advisor .............................       25
SECTION 8.10   Survival ......................................................       25
SECTION 8.11   Exculpation ...................................................       25

                                       ARTICLE IX
                                        AMENDMENT

SECTION 9.1    Amendment Without Consent of Holders ..........................       26
SECTION 9.2    Amendment with Consent of Holders .............................       26
SECTION 9.3    Execution of Amendments .......................................       27
SECTION 9.4    Effect of Amendments ..........................................       27
SECTION 9.5    Reference to Amendments .......................................       27

                                        ARTICLE X
                                      MISCELLANEOUS

SECTION 10.1   No Waiver .....................................................       28
SECTION 10.2   GOVERNING LAW .................................................       28
SECTION 10.3   Notices .......................................................       29
SECTION 10.4   Successors and Assigns ........................................       29
SECTION 10.5   Counterparts ..................................................       29
SECTION 10.6   Severability ..................................................       29
SECTION 10.7   Expenses, Etc .................................................       29
SECTION 10.8   Security Interest Absolute ....................................       30
SECTION 10.9   Waiver of Jury Trial ..........................................       30


EXHIBIT A      Instruction from Purchase Contract Agent to Collateral Agent
EXHIBIT B      Instruction to Purchase Contract Agent
EXHIBIT C      Instruction to Custodial Agent Regarding Remarketing
EXHIBIT D      Instruction to Custodial Agent Regarding Withdrawal from
               Remarketing
</TABLE>

<PAGE>

                                PLEDGE AGREEMENT

      PLEDGE AGREEMENT, dated as of November 1, 2002 (this "Agreement"), among
Platinum Underwriters Holdings, Ltd., a Bermuda corporation (the "Company"),
State Street Bank and Trust Company, a Massachusetts trust company, not
individually but solely as collateral agent (in such capacity, together with its
successors in such capacity, the "Collateral Agent"), as custodial agent (in
such capacity, together with its successors in such capacity, the "Custodial
Agent") and as "securities intermediary" as defined in Section 8-102(a)(14) of
the Code (as defined herein) (in such capacity, together with its successors in
such capacity, the "Securities Intermediary"), and JPMorgan Chase Bank, a New
York banking corporation, not individually but solely as purchase contract agent
and as attorney-in-fact of the Holders from time to time of the Units (in such
capacity, together with its successors in such capacity, the "Purchase Contract
Agent") under the Purchase Contract Agreement (as defined herein).

                                    RECITALS

      WHEREAS, the Company and the Purchase Contract Agent are parties to the
Purchase Contract Agreement, dated as of the date hereof (as modified and
supplemented and in effect from time to time, the "Purchase Contract
Agreement"), pursuant to which there may be issued Units having a Stated Amount
of $25 per Unit, all of which will initially be Normal Units.

      WHEREAS, each Normal Unit will be comprised of (a) a Purchase Contract and
(b) either beneficial ownership of (i) a 1/40, or 2.5%, beneficial ownership
interest in a Note having a $1,000 principal amount or (ii) following the
remarketing of the Notes in accordance with the Purchase Contract Agreement and
the Remarketing Agreement or if the Holder has elected not to have the Note
remarketed or a Tax Event Redemption in accordance with the Purchase Contract
Agreement and the terms of the Notes, beneficial ownership of the appropriate
Treasury Consideration.

      WHEREAS, in accordance with the terms of the Purchase Contract Agreement,
a holder of Normal Units may separate the Notes or the appropriate Treasury
Consideration, as applicable, from the related Purchase Contracts by
substituting for such Notes or the appropriate Treasury Consideration, as the
case may be, Treasury Securities that will pay in the aggregate an amount equal
to the aggregate Stated Amount of such Normal Units. Upon such separation, the
Normal Units will become Stripped Units. Each Stripped Unit will be comprised of
(a) a Purchase Contract and (b) a 1/40 undivided beneficial interest in a
Treasury Security.

      WHEREAS, pursuant to the terms of the Purchase Contract Agreement and the
Purchase Contracts, the Holders, from time to time, of the Units have
irrevocably authorized the Purchase Contract Agent, as attorney-in-fact of such
Holders, among other things, to execute and deliver this Agreement on behalf of
such Holders and to grant the pledge provided hereby of the Notes, any Treasury
Consideration and any Treasury

<PAGE>

Securities delivered in exchange therefor to secure each Holder's obligations
under the related Purchase Contract, as provided herein and subject to the terms
hereof.

      NOW, THEREFORE, and for other good and valuable consideration, the receipt
and sufficiency of which is hereby acknowledged, the Company, the Collateral
Agent, the Securities Intermediary, the Custodial Agent and the Purchase
Contract Agent, on its own behalf and as attorney-in-fact of the Holders from
time to time of the Units, agree as follows:

                                    ARTICLE I

                                   DEFINITIONS

SECTION 1.1 Definitions

      For all purposes of this agreement, except as otherwise expressly provided
or unless the context otherwise requires:

      (a) capitalized terms used but not defined herein are used as defined in
the Purchase Contract Agreement;

      (b) the defined terms in this Agreement have the meanings assigned to them
in this Article and include the plural as well as the singular; and

      (c) the words "herein," "hereof" and "hereunder" and other words of
similar import refer to this Agreement as a whole and not to any particular
Article, Section or other subdivision.

      "Agreement" means this agreement as originally executed or as it may from
time to time be supplemented or amended by one or more agreements supplemental
hereto entered into pursuant to the applicable provisions hereof.

      "Code" has the meaning specified in Section 6.1 hereof.

      "Collateral" has the meaning specified in Section 2.1 hereof.

      "Collateral Account" means the securities account (number 131404-015)
maintained at State Street Bank and Trust Company in the name "JPMorgan Chase
Bank, as Purchase Contract Agent on behalf of the holders of certain securities
of Platinum Underwriters Holdings, Ltd., Collateral Account subject to the
security interest of State Street Bank and Trust Company, as Collateral Agent,
for the benefit of Platinum Underwriters Holdings, Ltd., as pledgee" and any
successor account.

      "Collateral Agent" has the meaning specified in the first paragraph of
this Agreement.


                                          -2-
<PAGE>

      "Company" means the Person named as the "Company" in the first paragraph
of this Agreement until a successor shall have become such, and thereafter
"Company" shall mean such successor.

      "Custodial Agent" has the meaning specified in the first paragraph of this
Agreement.

      "Intermediary" means any entity that in the ordinary course of its
business maintains securities accounts for others and is acting in that
capacity.

      "Pledge" has the meaning specified in Section 2.1 hereof.

      "Pledged Notes" has the meaning specified in Section 2.1 hereof.

      "Pledged Treasury Consideration" has the meaning specified in Section 2.1,
hereof.

      "Pledged Treasury Securities" has the meaning specified in Section 2.1
hereof.

      "Proceeds" means all interest, dividends, cash, instruments, securities,
financial assets (as defined in Section 8-l02(a)(9) of the Code) and other
property from time to time received, receivable or otherwise distributed upon
the sale, exchange, collection or disposition of the Collateral or any proceeds
thereof.

      "Purchase Contract Agent" has the meaning specified in the first paragraph
of this Agreement.

      "Purchase Contract Agreement" has the meaning specified in the Recitals.

"Securities Intermediary" has the meaning specified in the first paragraph of
this Agreement.

      "Security Entitlement" has the meaning set forth in Section 8-102(a)(17)
of the Code.

      "Separate Notes" means any Notes that are not Pledged Notes.

      "TRADES Regulations" means the regulations of the United States Department
of the Treasury, published at 31 C.F.R. Part 357, as amended from time to time.
Unless otherwise defined herein, all terms defined in the TRADES Regulations are
used herein as therein defined.

      "Transfer" means, with respect to the Collateral and in accordance with
the instructions of the Collateral Agent, the Purchase Contract Agent or the
Holder, as applicable:


                                      -3-
<PAGE>

      (i)   in the case of Collateral consisting of securities which cannot be
            delivered by book-entry or which the parties agree are to be
            delivered in physical form, delivery in appropriate physical form to
            the recipient accompanied by any duly executed instruments of
            transfer, assignments in blank, transfer tax stamps and any other
            documents necessary to constitute a legally valid transfer to the
            recipient;

      (ii)  in the case of Collateral consisting of securities maintained in
            book-entry form by causing a "securities intermediary" (as defined
            in Section 8-l02(a)(l4) of the Code) to (a) credit a "security
            entitlement" (as defined in Section 8-102(a)(17) of the Code) with
            respect to such securities to a "securities account" (as defined in
            Section 8-501(a) of the Code) maintained by or on behalf of the
            recipient and (b) to issue a confirmation to the recipient with
            respect to such credit. In the case of Collateral to be delivered to
            the Collateral Agent, the securities intermediary shall be the
            Securities Intermediary and the securities account shall be the
            Collateral Account. In addition, any Transfer of Treasury Securities
            and Treasury Consideration hereunder shall be made in accordance
            with the TRADES Regulations and other applicable law.

                                   ARTICLE II

                         PLEDGE; CONTROL AND PERFECTION

      SECTION 2.1 The Pledge

      (a) The Holders from time to time acting through the Purchase Contract
Agent, as their attorney-in-fact, and the Purchase Contract Agent, as such
attorney-in-fact, hereby pledge and grant to the Collateral Agent, for the
benefit of the Company, as collateral security for the performance when due by
such Holders of their respective obligations under the related Purchase
Contracts, a security interest in all of the right, title and interest of the
Purchase Contract Agent and such Holders in:

      (i)   (A) the Notes, Treasury Consideration or Treasury Securities
            constituting a part of the Units, (B) any Treasury Securities
            delivered in exchange for any Notes or Treasury Consideration, as
            applicable, in accordance with Section 4.1 hereof, and (C) any Notes
            or Treasury Consideration, as applicable, delivered in exchange for
            any Treasury Securities in accordance with Section 4.2 hereof, in
            each case that have been Transferred to or otherwise received by the
            Collateral Agent and not released by the Collateral Agent to such
            Holders under the provisions of this Agreement;


                                      -4-
<PAGE>

      (ii)  the Collateral Account and all securities, financial assets,
            security entitlements, cash and other property credited thereto and
            all Security Entitlements related thereto; and

      (iii) all Proceeds of the foregoing (all of the foregoing, collectively,
            the "Collateral").

      (b) Prior to or concurrently with the execution and delivery of this
Agreement, the Purchase Contract Agent, on behalf of the initial Holders of the
Units, shall cause the Notes comprising a part of the Normal Units to be
Transferred to the Collateral Agent for the benefit of the Company.

      (c) The pledge provided in this Section 2.1 is herein referred to as the
"Pledge" and the Notes (including any Notes that are delivered pursuant to
Section 6.2 hereof), Treasury Consideration and Treasury Securities subject to
the Pledge, excluding any Notes, Treasury Consideration or Treasury Securities
released from the Pledge as provided in Sections 4.1 and 4.2 hereof,
respectively, are hereinafter referred to as "Pledged Notes," "Pledged Treasury
Consideration" and "Pledged Treasury Securities," respectively. Subject to the
Pledge and the provisions of Section 2.2 hereof, the Holders from time to time
shall have fill beneficial ownership of the Collateral. For purposes of
perfecting the Pledge under applicable law, including, to the extent applicable,
the TRADES Regulations or the Uniform Commercial Code as adopted and in effect
in any applicable jurisdiction, the Collateral Agent shall be the agent of the
Company as provided herein. Whenever directed by the Collateral Agent acting on
behalf of the Company, the Securities Intermediary shall have the right to
reregister the Notes or any other securities held in physical form in its name.

      (d) Except as may be required in order to release Notes or Treasury
Consideration, as applicable, in connection with a Tax Event Redemption or with
a Holder's election to convert its investment from a Normal Unit to a Stripped
Unit, or except as otherwise required to release Notes as specified herein,
neither the Collateral Agent, the Custodial Agent nor the Securities
Intermediary shall relinquish physical possession of any certificate evidencing
Notes, Treasury Securities or Treasury Consideration, as applicable, prior to
the termination of this Agreement. If it becomes necessary for the Securities
Intermediary to relinquish physical possession of a certificate in order to
release a portion of the Notes evidenced thereby from the Pledge, the Collateral
Agent shall use its best efforts to obtain physical possession of a replacement
certificate evidencing any Notes remaining subject to the Pledge hereunder
registered to it or endorsed in blank within fifteen days of the date it
relinquished possession. The Collateral Agent shall promptly notify the Company
of its inability to obtain possession of any such replacement certificate as
required hereby.


                                      -5-
<PAGE>

      SECTION 2.2 Control and Perfection

      (a) In connection with the Pledge granted in Section 2.1, and subject to
the other provisions of this Agreement, the Holders from time to time acting
through the Purchase Contract Agent, as their attorney-in-fact, hereby authorize
and direct the Securities Intermediary (without the necessity of obtaining the
further consent of the Purchase Contract Agent or any of the Holders), and the
Securities Intermediary agrees, to comply with and follow any instructions and
entitlement orders (as defined in Section 8-102(a)(8) of the Code) that the
Collateral Agent may deliver pursuant to the terms hereof or upon the written
direction of the Company with respect to the Collateral Account, the Collateral
credited thereto and any Security Entitlements with respect to any thereof. In
the event the Securities Intermediary receives from the Holders or the Purchase
Contract Agent entitlement orders which conflict with entitlement orders
received from the Collateral Agent, the Securities Intermediary shall follow the
entitlement orders received from the Collateral Agent. Such instructions and
entitlement orders may, without limitation, direct the Securities Intermediary
to transfer, redeem, assign, or otherwise deliver the Notes, the Treasury
Consideration and the Treasury Securities, and any Security Entitlements with
respect thereto or sell, liquidate or dispose of such assets through a broker
designated by the Company, and to pay and deliver any income, proceeds or other
funds derived therefrom to the Company. The Holders from time to time acting
through the Purchase Contract Agent hereby further authorize and direct the
Collateral Agent, as agent of the Company, to, pursuant to the terms hereof or
upon written direction of the Company, itself issue instructions and entitlement
orders, and to otherwise take action, with respect to the Collateral Account,
the Collateral credited thereto and any Security Entitlements with respect
thereto, pursuant to the terms and provisions hereof, all without the necessity
of obtaining the further consent of the Purchase Contract Agent or any of the
Holders. The Collateral Agent shall be the agent of the Company and shall act
only in accordance with the terms hereof or as otherwise directed in writing by
the Company. Without limiting the generality of the foregoing, the Collateral
Agent shall issue entitlement orders to the Securities Intermediary when and as
required by the terms hereof or as otherwise directed in writing by the Company.

      (b) The Securities Intermediary hereby confirms and agrees that:

      (i)   all securities or other property underlying any financial assets
            credited to the Collateral Account shall be registered in the name
            of the Securities Intermediary, or its nominee, indorsed to the
            Securities Intermediary, or its nominee, or in blank or credited to
            another Collateral Account maintained in the name of the Securities
            Intermediary and in no case will any financial asset credited to the
            Collateral Account be registered in the name of the Purchase
            Contract Agent, the Collateral Agent, the Company or any Holder,
            payable to the order of, or specially indorsed to, the Purchase
            Contract Agent, the Collateral Agent, the Company or any Holder
            except to the extent the foregoing have been specially indorsed to
            the Securities Intermediary or in blank;


                                      -6-
<PAGE>

      (ii)  all property delivered to the Securities Intermediary pursuant to
            this Agreement (including, without limitation, any Notes, Treasury
            Consideration or Treasury Securities) will be promptly credited to
            the Collateral Account;

      (iii) the Collateral Account is an account to which financial assets are
            or may be credited, and the Securities Intermediary shall, subject
            to the terms of this Agreement, treat the Purchase Contract Agent as
            entitled to exercise the rights of any financial asset credited to
            the Collateral Account;

      (iv)  the Securities Intermediary has not entered into, and until the
            termination of this Agreement will not enter into, any agreement
            with any other Person relating to the Collateral Account and/or any
            financial assets credited thereto pursuant to which it has agreed to
            comply with entitlement orders (as defined in Section 8-102(a)(8) of
            the Code) of such other Person; and

      (v)   the Securities Intermediary has not entered into, and until the
            termination of this Agreement will not enter into, any agreement
            with the Company, the Collateral Agent or the Purchase Contract
            Agent purporting to limit or condition the obligation of the
            Securities Intermediary to comply with entitlement orders as set
            forth in this Section 2.2 hereof.

      (c) The Securities Intermediary hereby agrees that each item of property
(whether investment property, financial asset, security, instrument or cash)
credited to the Collateral Account shall be treated as a "financial asset"
within the meaning of Section 8-102(a)(9) of the Code.

      (d) In the event of any conflict between this Agreement (or any portion
thereof) and any other agreement now existing or hereafter entered into, the
terms of this Agreement shall prevail.

      (e) The Purchase Contract Agent hereby irrevocably constitutes and
appoints the Collateral Agent and the Company, with full power of substitution,
as the Purchase Contract Agent's attorney-in-fact to take on behalf of, and in
the name, place and stead of the Purchase Contract Agent and the Holders, any
action necessary or desirable to perfect and to keep perfected the security
interest in the Collateral referred to in Section 2.1. The grant of such
power-of-attorney shall not he deemed to require of the Collateral Agent any
specific duties or obligations not otherwise assumed by the Collateral Agent
hereunder. Notwithstanding the foregoing, in no event shall the Collateral Agent
or Securities Intermediary be responsible for the preparation or filing of any
financing or continuation statements in the appropriate jurisdictions or
responsible for maintenance or perfection of any security interest hereunder.


                                      -7-
<PAGE>

                                   ARTICLE III

                             PAYMENTS ON COLLATERAL

      SECTION 3.1 Payments

      So long as the Purchase Contract Agent is the registered owner of the
Pledged Notes, Pledged Treasury Consideration or Pledged Treasury Securities, it
shall receive all payments thereon. If the Pledged Notes are reregistered such
that the Collateral Agent becomes the registered holder, all payments of the
principal of, or interest on, the Pledged Notes and all payments of the
principal of, or cash distributions on, any Pledged Treasury Consideration or
Pledged Treasury Securities, that are received by the Collateral Agent and that
are properly payable hereunder shall be paid by the Collateral Agent by wire
transfer in same day funds:

      (i)   in the case of (A) quarterly cash distributions on Normal Units
            which include Pledged Notes or Pledged Treasury Consideration, as
            the case may be, and (B) any payments of principal or, if
            applicable, any Tax Event Redemption Treasury Consideration (as
            specified in clause (B) of the definition of such term) with respect
            to any Notes or Treasury Consideration, as the case may be, that
            have been released from the Pledge pursuant to Section 4.3 hereof,
            to the Purchase Contract Agent, for the benefit of the relevant
            Holders of the Normal Units, to the account designated by the
            Purchase Contract Agent for such purpose no later than 11:00a.m.,
            New York City time, on the Business Day such payment is received by
            the Collateral Agent (provided that in the event such payment or
            payment instructions are received by the Collateral Agent after 9:00
            a.m., New York City time, on a Business Day, then such payment shall
            be made no later than 10:30, New York City time, on the next
            succeeding Business Day and in the event such payment or payment
            instructions are received by the Collateral Agent on a day that is
            not a Business Day, then such payment shall be made no later than
            12:00 p.m., New York City time, on the next succeeding Business
            Day);

      (ii)  in the case of any payments with respect to any Treasury Securities
            that have been released from the Pledge pursuant to Section 4.3
            hereof to the Holders of the Stripped Units, to the accounts
            designated by the Purchase Contract Agent in writing for such
            purpose no later than 2:00 p.m., New York City time, on the Business
            Day such payment is received by the Collateral Agent (provided that
            in the event such payment or payment instructions are received by
            the Collateral Agent after 10:00 a.m., New York City time, on a
            Business Day, then such payment shall be made no later than 10:30,
            New York City time, on the next succeeding Business Day and in the
            event such payment or payment instructions are received by the
            Collateral Agent on a day that is not a Business Day, then such


                                      -8-
<PAGE>

            payment shall be made no later than 12:00p.m., New York City time,
            on the next succeeding Business Day); any payment to be made
            directly to the Holders of such Stripped Units shall be subject to
            applicable federal withholding law, including the requirement that a
            Holder shall have provided to the Collateral Agent its certified
            taxpayer identification number by furnishing appropriate Forms W-9
            (or such other forms as shall be applicable);

      (iii) in the case of payments in respect of any Pledged Notes, Pledged
            Treasury Consideration or Pledged Treasury Securities, as the case
            may be, to be paid upon settlement of such Holder's obligations to
            purchase Common Shares under the Purchase Contract, to the Company
            on the Share Purchase Date in accordance with the procedure set
            forth in Section 4.5(a) or 4.5(b) hereof, in full satisfaction of
            the respective obligations of the Holders under the related Purchase
            Contracts; and

      (iv)  in the case of any payments in respect of any Pledged Notes upon a
            Prepayment Event, in accordance with the written instructions of the
            Purchase Contract Agent for the purchase of the Prepayment Treasury
            Consideration and as set forth in Section 4.5 of the Purchase
            Contract Agreement.

      SECTION 3.2 Application of Payments

      All payments received by the Purchase Contract Agent as provided herein
shall be applied by the Purchase Contract Agent pursuant to the provisions of
the Purchase Contract Agreement. If, notwithstanding the foregoing, the Purchase
Contract Agent shall receive any payments of principal on account of any Notes
or Treasury Consideration, as applicable, that, at the time of such payment, are
Pledged Notes or Pledged Treasury Consideration, as the case may be (other than
payments to which it is entitled pursuant to the terms of the Purchase Contract
Agreement), or a Holder of a Stripped Unit shall receive any payments of
principal on account of any Treasury Securities that, at the time of such
payment, are Pledged Treasury Securities (other than payments to which it is
entitled pursuant to the terms of the Purchase Contract Agreement), the Purchase
Contract Agent or such Holder shall hold the same as trustee of an express trust
for the benefit of the Company (and promptly deliver the same over to the
Company) for application to the obligations of the Holders under the related
Purchase Contracts, and the Holders shall acquire no right, title or interest in
any such payments of principal so received.


                                      -9-
<PAGE>

                                   ARTICLE IV

            SUBSTITUTION, RELEASE, REPLEDGE AND SETTLEMENT OF NOTES

      SECTION 4.1 Collateral Substitution and the Creation of Stripped Units

      At any time on or prior to the second Business Day immediately preceding
the Share Purchase Date, a Holder of Normal Units shall have the right to
substitute Treasury Securities for the Pledged Notes or Pledged Treasury
Consideration, as the case may be, securing such Holder's obligations under the
Purchase Contracts comprising a part of such Normal Units, in integral multiples
of 40 Normal Units, or after a successful remarketing of the Notes pursuant to
the Purchase Contract Agreement or a Tax Event Redemption, in integral multiples
of Normal Units so that Treasury Securities to be deposited and the applicable
Treasury Consideration, as the case may be, to be released are in integral
multiples of $1,000, by (a) Transferring to the Collateral Agent Treasury
Securities having an aggregate principal amount equal to the aggregate Stated
Amount of such Normal Units and (b) delivering such Normal Units to the Purchase
Contract Agent, accompanied by a notice, substantially in the form of Exhibit 13
hereto, to the Purchase Contract Agent stating that such Holder has Transferred
Treasury Securities to the Collateral Agent pursuant to clause (a) above
(stating the principal amount, the maturities and the CUSIP numbers of the
Treasury Securities Transferred by such Holder) and requesting that the Purchase
Contract Agent instruct the Collateral Agent to release from the Pledge the
Pledged Notes or Pledged Treasury Consideration related to such Normal Units,
whereupon the Purchase Contract Agent shall promptly give such instruction to
the Collateral Agent in the form provided in Exhibit A; provided that such
Holder may not substitute such Treasury Securities for such Pledged Notes or
Pledged Treasury Consideration pursuant to this Section 4.1 after a Prepayment
Event or during the period from four Business Days prior to any Remarketing
Period until the expiration of three Business Days after the end of such
Remarketing Period. Upon receipt of Treasury Securities from a Holder of Normal
Units and the related instruction from the Purchase Contract Agent, the
Collateral Agent shall release the Pledged Notes or Pledged Treasury
Consideration and shall promptly Transfer such Pledged Notes or Pledged Treasury
Consideration free and clear of any lien, pledge or security interest created
hereby, to the Purchase Contract Agent. All items Transferred and/or substituted
by any Holder pursuant to this Section 4.1, Section 4.2 or any other Section of
this Agreement shall be Transferred and/or substituted free and clear of all
liens, claims and encumbrances.

      SECTION 4.2 Collateral Substitution and the Re-Creation of Normal Units

      At any time on or prior to the second Business Day immediately preceding
the Share Purchase Date, a Holder of Stripped Units shall have the right to
reestablish Normal Units (a) consisting of the Purchase Contracts and Notes in
integral multiples of 40 Normal Units, or (b) after a remarketing of the Notes
pursuant to the Purchase Contract Agreement or a Tax Event Redemption,
consisting of the Purchase Contracts and the appropriate Treasury Consideration
(identified and calculated by reference to the


                                      -10-
<PAGE>

      Treasury Consideration then comprising Normal Units) or the appropriate
portion of the Treasury Portfolio in integral multiples of Stripped Units so
that the Treasury Consideration to be deposited and the Treasury Securities to
be released are in integral multiples of $l,000, by (x) Transferring to the
Collateral Agent Notes or the appropriate Treasury Consideration, as the case
may be, then comprising such number of Normal Units as is equal to such Stripped
Units and (y) delivering such Stripped Units to the Purchase Contract Agent,
accompanied by a notice, substantially in the form of Exhibit B hereto, to the
Purchase Contract Agent stating that such Holder has transferred Notes or
Treasury Consideration to the Collateral Agent pursuant to clause (a) above and
requesting that the Purchase Contract Agent instruct the Collateral Agent to
release from the Pledge the Pledged Treasury Securities related to such Stripped
Units, whereupon the Purchase Contract Agent shall give such instruction to the
Collateral Agent in the form provided in Exhibit A. Upon receipt of the Notes or
the appropriate Treasury Consideration, as the case may be, from such Holder and
the instruction from the Purchase Contract Agent, the Collateral Agent shall
release the Pledged Treasury Securities and shall promptly Transfer such
Treasury Securities, free and clear of any lien, pledge or security interest
created hereby, to the Purchase Contract Agent.

      SECTION 4.3 Termination Event

      (a) Upon receipt by the Collateral Agent of written notice from the
Company or the Purchase Contract Agent that there has occurred a Termination
Event and identifying the nature of the Termination Event, the Collateral Agent
shall release all Collateral from the Pledge and shall promptly Transfer any
Pledged Notes or Pledged Treasury Consideration, as the case may be, and Pledged
Treasury Securities to the Purchase Contract Agent for the benefit of the
Holders of the Normal Units and the Stripped Units, respectively, free and clear
of any lien, pledge or security interest or other interest created in favor of
the Collateral Agent hereby.

      (b) If such Termination Event shall result from the Company's becoming a
debtor under the Bankruptcy Code, and if the Collateral Agent shall advise the
Purchase Contract Agent in writing that the Collateral Agent shall for any
reason be prohibited from promptly effectuating the release and Transfer of all
Pledged Notes, Pledged Treasury Consideration or Pledged Treasury Securities, as
the case may be, as provided by this Section 4.3, the Purchase Contract Agent
shall:

      (i)   use its reasonable best efforts to obtain an opinion of a nationally
            recognized law firm reasonably acceptable to the Collateral Agent to
            the effect that, as a result of the Company's being the debtor in
            such a bankruptcy case, the Collateral Agent will not be prohibited
            from releasing or Transferring the Collateral as provided in this
            Section 4.3, and shall deliver such opinion to the Collateral Agent
            within ten days after the occurrence of such Termination Event, and
            if (y) the Purchase Contract Agent shall be unable to obtain such
            opinion within ten days after the occurrence of such Termination
            Event or (z) the Collateral Agent shall


                                      -11-
<PAGE>

            continue, after delivery of such opinion, to refuse to effectuate
            the release and Transfer of all Pledged Notes, Pledged Treasury
            Consideration or Pledged Treasury Securities, as the case may be, as
            provided in this Section 4.3, then the Purchase Contract Agent shall
            within fifteen days after the occurrence of such Termination Event
            commence an action or proceeding in the court with jurisdiction of
            the Company's case under the Bankruptcy Code seeking an order
            requiring the Collateral Agent to effectuate the release and
            transfer of all Pledged Notes, Pledged Treasury Consideration or
            Pledged Treasury Securities, as the case may be, as provided by this
            Section 4.3 or

      (ii) commence an action or proceeding like that described in subsection
      (i) hereof within ten days after the occurrence of such Termination Event.

      SECTION 4.4 Early Settlement; Merger Early Settlement; Cash Settlement

      Upon written notice to the Collateral Agent by the Purchase Contract Agent
that one or more Holders of Units have elected to effect Early Settlement,
Merger Early Settlement or Cash Settlement of their respective obligations under
the Purchase Contracts forming a part of such Units in accordance with the terms
of the Purchase Contracts and the Purchase Contract Agreement (setting forth the
number of such Purchase Contracts as to which such Holders have elected to
effect Early Settlement, Merger Early Settlement or Cash Settlement), and that
the Purchase Contract Agent has received from such Holders, and paid to the
Company as confirmed in writing by the Company, the related Early Settlement
Amounts, Merger Early Settlement Amounts or Cash Settlement Amounts, as the case
may be, pursuant to the terms of the Purchase Contracts and the Purchase
Contract Agreement and that all conditions to such Early Settlement, Merger
Early Settlement or Cash Settlement, as the case may be, have been satisfied,
then the Collateral Agent shall release from the Pledge (a) Pledged Notes or
Pledged Treasury Consideration, as the case may be, in the case of a Holder of
Normal Units or (b) Pledged Treasury Securities, in the case of a Holder of
Stripped Units, identified by the Purchase Contract Agent as relating to such
Purchase Contracts as to which such Holders have elected to effect Early
Settlement, Merger Early Settlement or Cash Settlement, and shall Transfer all
such Pledged Notes, Pledged Treasury Consideration or Pledged Treasury
Securities, as the case may be, free and clear of any lien, pledge or security
interest created hereby, to the Purchase Contract Agent for the benefit of the
Holders.

      SECTION 4.5 Remarketing; Application of Proceeds; Settlement

      (a) Pursuant to the Purchase Contract Agreement, the Purchase Contract
Agent shall notify, by 10:00 a.m., New York City time, on the third Business Day
preceding the first day of any Remarketing Period, the Remarketing Agent and the
Collateral Agent of the aggregate principal amount of Notes comprising part of
Normal Units to be remarketed. The Collateral Agent shall, by 10:00 a.m., New
York City time,


                                      -12-
<PAGE>

on the Business Day immediately preceding the first day of any Remarketing
Period, without any instruction from Holders of Normal Units, deliver (i) the
Pledged Notes to be remarketed to the Remarketing Agent for remarketing and (ii)
the remaining Pledged Notes to the Purchase Contract Agent for distribution to
the Holders that have elected not to participate in the remarketing in
accordance with the Purchase Contract Agreement. The Remarketing Agent will
agree pursuant to the Remarketing Agreement to deliver the Agent-purchased
Treasury Consideration purchased from the proceeds of a successful remarketing
to the Purchase Contract Agent, which shall thereupon deliver such
Agent-purchased Treasury Consideration to the Collateral Agent. Upon receipt of
the Agent-purchased Treasury Consideration from the Purchase Contract Agent
following a successful remarketing, the Collateral Agent, for the benefit of the
Company, shall thereupon hold such Agent-purchased Treasury Consideration to
secure such Holders' obligations under the Purchase Contracts. On the Share
Purchase Date, the Collateral Agent shall apply that portion of the payments
received in respect of the Pledged Treasury Consideration equal to the aggregate
Stated Amount of the related Normal Units to satisfy in full the obligations of
such Holders of Normal Units to pay the Purchase Price under the related
Purchase Contracts. The remaining portion of such Proceeds, if any, shall be
distributed by the Collateral Agent to the Purchase Contract Agent for payment
to each Holder of a Normal Unit a cash payment in an amount equal to 1/40, or
2.5%, of a quarterly interest payment on the $1,000 principal amount of a Senior
Note at the initial annual rate of 5.25%.

      (b) Promptly following a Failed Remarketing, the Notes delivered to the
Remarketing Agent and the Purchase Contract Agent pursuant to Section 4.5(a)
shall be returned to the Collateral Agent, together with written notice from the
Remarketing Agent of the Failed Remarketing. The Collateral Agent, for the
benefit of the Company, shall thereupon hold such Notes to secure the
obligations of Holders of Normal Units under the Purchase Contracts. The
Remarketing Agent shall agree to make one or more attempts to remarket the Notes
in accordance with the procedures set forth in the Purchase Contract Agreement
and the Remarketing Agreement between the Remarketing Date and the Share
Purchase Date, provided that the requirements of Section 5.4(b)(ii) of the
Purchase Contract Agreement have been met. If by 4:00 p.m., New York City time,
on the third Business Day immediately preceding the Share Purchase Date the
Remarketing Agent has failed to remarket the Notes at a price equal to at least
100.25% of the Remarketing Value (as described in the Purchase Contract
Agreement), the "Last Failed Remarketing" shall be deemed to have occurred. In
this case, the Remarketing Agent will agree to advise the Collateral Agent in
writing that it cannot remarket the related Pledged Notes of such Holders of
Normal Units and the Remarketing Agent will agree pursuant to the Remarketing
Agreement to promptly return to the Collateral Agent the Notes delivered to it
pursuant to Section 4.5(a). The Collateral Agent, for the benefit of the Company
will, at the written direction of the Company, deliver or dispose of the Pledged
Notes in accordance with the Company's written instructions to satisfy in full,
from any such disposition or retention, such Holders' obligations to pay the
Purchase Price for the Common Shares; provided that if upon a Failed Remarketing
or the Last Failed Remarketing, as the case may be, the Collateral Agent
delivers or disposes of the


                                      -13-
<PAGE>

Pledged Notes in accordance with the written instructions of the Company, any
accrued and unpaid interest on such Notes will become payable by the Company to
the Purchase Contract Agent for payment to the Holder of the Normal Units to
which such Notes relate in accordance with the Purchase Contract Agreement.

      (c) In the event a Holder of Stripped Units has not made an Early
Settlement, Merger Early Settlement or Cash Settlement of the Purchase Contracts
underlying its Stripped Units, such Holder shall be deemed to have elected to
pay for the Common Shares to be issued under such Purchase Contracts from the
payments received in respect of the related Pledged Treasury Securities. Without
receiving any instruction from any such Holder of Stripped Units, the Collateral
Agent shall apply such payments to the settlement of such Purchase Contracts on
the Share Purchase Date pursuant to written instructions from the Purchase
Contract Agent. In the event the payments received in respect of the related
Pledged Treasury Securities are in excess of the aggregate Purchase Price of the
Purchase Contracts being settled thereby, the Collateral Agent shall distribute
such excess, when received, to the Purchase Contract Agent for payment to such
Holders of Stripped Units.

      (d) Pursuant to the Remarketing Agreement and Purchase Contract Agreement,
on or prior to the fourth Business Day preceding the first day of any
Remarketing Period, but no earlier than the Payment Date immediately preceding
the first day of such Remarketing Period, holders of Separate Notes may elect to
have their Separate Notes remarketed by delivering their Separate Notes,
together with a notice of such election, substantially in the form of Exhibit C
hereto, to the Custodial Agent. On the third Business Day prior to the first day
of any Remarketing Period, by 10:00 a.m., New York City time, the Custodial
Agent shall notify the Remarketing Agent of the principal amount of such
Separate Notes to be remarketed. The Custodial Agent will hold such Separate
Notes in an account separate from the Collateral Account. A holder of Separate
Notes electing to have its Separate Notes remarketed will also have the right to
withdraw such election by written notice to the Custodial Agent, substantially
in the form of Exhibit D hereto, on or prior to the fourth Business Day
immediately preceding the first day of any Remarketing Period, upon which notice
the Custodial Agent will return such Separate Notes to such holder. On the
Business Day immediately preceding the first day of any Remarketing Period, the
Custodial Agent will deliver to the Remarketing Agent for remarketing all
Separate Notes delivered to the Custodial Agent pursuant to this Section 4.5(d)
and not withdrawn pursuant to the terms hereof prior to such date. The portion
of the proceeds from such remarketing equal to the amount calculated in respect
of such Separate Notes as set forth in Section 5.4(b) of the Purchase Contract
Agreement will automatically be remitted by the Remarketing Agent to the
Custodial Agent for the benefit of the holders of such Separate Notes. In
addition, after deducting as the remarketing fee an amount not exceeding 25
basis points (.25%) of the total proceeds of such remarketing of such Separate
Notes, the Remarketing Agent will remit to the Custodial Agent the remaining
portion of the proceeds, if any, for payment to such holders. If, despite using
commercially reasonable best efforts, the Remarketing Agent advises the
Custodial Agent in writing that there has been a Failed Remarketing,


                                      -14-
<PAGE>

the Remarketing Agent will promptly return such Notes to the Custodial Agent for
redelivery to the holders of such Separate Notes. For purposes of this Section
4.5(d), a "holder" of a Separate Notes shall mean the Person in whose name such
Separate Notes is registered on the books of the registrar for the Notes.

                                   ARTICLE V

                             VOTING RIGHTS -- NOTES

      SECTION 5.1 Exercise by Purchase Contract Agent

      The Purchase Contract Agent may exercise, or refrain from exercising, any
and all voting and other consensual rights pertaining to the Pledged Notes or
any part thereof for any purpose not inconsistent with the terms of this
Agreement and in accordance with the terms of the Purchase Contract Agreement;
provided that the Purchase Contract Agent shall not exercise or, as the case may
be, shall not refrain from exercising such right if, in the judgment of the
Company, such action would impair or otherwise have a material adverse effect on
the value of all or any of the Pledged Notes; and provided, further, that the
Purchase Contract Agent shall give the Company and the Collateral Agent at least
five Business Days' prior written notice of the manner in which it intends to
exercise, or its reasons for refraining from exercising, any such right. Upon
receipt of any notices and other communications in respect of any Pledged Notes,
including notice of any meeting at which holders of Notes are entitled to vote
or solicitation of consents, waivers or proxies of holders of Notes, the
Collateral Agent shall use reasonable efforts to send promptly to the Purchase
Contract Agent such notice or communication, and as soon as reasonably
practicable after receipt of a written request therefor from the Purchase
Contract Agent, execute and deliver to the Purchase Contract Agent such proxies
and other instruments in respect of such Pledged Notes (in form and substance
satisfactory to the Collateral Agent) as are prepared by the Purchase Contract
Agent with respect to the Pledged Notes.

                                   ARTICLE VI

                   RIGHTS AND REMEDIES; TAX EVENT REDEMPTION

      SECTION 6.1 Rights and Remedies of the Collateral Agent

      (a) In addition to the rights and remedies available at law or in equity,
after an event of default under the Purchase Contracts, the Collateral Agent
shall have all of the rights and remedies with respect to the Collateral of a
secured party under the Uniform Commercial Code (or any successor thereto) as in
effect in the State of New York from time to time (the "Code") (whether or not
the Code is in effect in the jurisdiction where the rights and remedies are
asserted) and the TRADES Regulations and such additional rights and remedies to
which a secured party is entitled under the laws in effect in any


                                      -15-
<PAGE>

jurisdiction where any rights and remedies hereunder may be asserted. Wherever
reference is made in this Agreement to any section of the Code, such reference
shall be deemed to include a reference to any provision of the Code which is a
successor to, or amendment of, such section. Without limiting the generality of
the foregoing, such remedies may include, to the extent permitted by applicable
law, (i) retention of the Pledged Notes or other Collateral in full satisfaction
of the Holders' obligations under the Purchase Contracts or (ii) sale of the
Pledged Notes or other Collateral in one or more public or private sales or
otherwise at the written direction of the Company.

      (b) Without limiting any rights or powers otherwise granted by this
Agreement to the Collateral Agent, in the event the Collateral Agent is unable
to make payments to the Company on account of any Pledged Treasury Consideration
or Pledged Treasury Securities as provided in Article III hereof in satisfaction
of the obligations of the Holder of the Units of which such Pledged Treasury
Consideration or Pledged Treasury Securities, as applicable, is a part under the
related Purchase Contracts, the inability to make such payments shall constitute
an event of default under the Purchase Contracts and the Collateral Agent shall
have and may exercise, with reference to such Pledged Treasury Securities or
such Pledged Treasury Consideration, as applicable, and such obligations of such
Holder, any and all of the rights and remedies available to a secured party
under the Code and the TRADES Regulations after default by a debtor, and as
otherwise granted herein or under any other law.

      (c) Without limiting any rights or powers otherwise granted by this
Agreement to the Collateral Agent, the Collateral Agent is hereby irrevocably
authorized to receive and collect all payments of (i) the principal amount of,
or interest on, the Pledged Notes, or (ii) the principal amount of the Pledged
Treasury Consideration or Pledged Treasury Securities, subject, in each case, to
the provisions of Article III, and as otherwise granted herein.

      (d) The Purchase Contract Agent, individually and as attorney-in-fact for
each Holder of Units, agrees that, from time to time, upon the written request
of the Company or the Collateral Agent (acting upon the written request of the
Company), the Purchase Contract Agent or such Holder shall execute and deliver
such further documents and do such other acts and things as may be necessary,
including as the Company or the Collateral Agent (acting upon the written
request of the Company) may reasonably request in order to maintain the Pledge,
and the perfection and priority thereof, and to confirm the rights of the
Collateral Agent hereunder. The Purchase Contract Agent shall have no liability
to any Holder for executing any documents or taking any such acts requested by
the Company or the Collateral Agent (acting upon the written request of the
Company) hereunder, except for liability for its own negligent act, its own
negligent failure to act, its own bad faith or its own willful misconduct.

      (e) The Collateral Agent shall not be deemed to have knowledge of any
event of default unless it has received notice thereof from the Company or the
Purchase Contract Agent.


                                      -16-
<PAGE>

      SECTION 6.2 Substitutions

      Whenever a Holder has the right to substitute Treasury Securities, Notes,
or Treasury Consideration, as the case may be, for Collateral held by the
Collateral Agent, such substitution shall not constitute a novation of the
security interest created hereby.

      SECTION 6.3 Tax Event Redemption

      Upon the occurrence of a Tax Event Redemption prior to the Share Purchase
Date or the earlier successful remarketing of the Notes pursuant to Section 5.4
of the Purchase Contract Agreement and the receipt of the Redemption Price of
the Pledged Notes by the Collateral Agent, the Collateral Agent will, at the
written direction of the Company, apply the Redemption Price to purchase on
behalf of the Holders of Normal Units the Tax Event Redemption Treasury
Consideration. The Collateral Agent shall transfer the Tax Event Redemption
Treasury Consideration to the Collateral Account to secure the obligation of all
Holders of Normal Units to purchase Common Shares of the Company under the
Purchase Contracts constituting a part of such Normal Units, in substitution for
the Pledged Notes. Thereafter the Collateral Agent shall have such security
interests, rights and obligations with respect to the Tax Event Redemption
Treasury Consideration as it had in respect of the Pledged Notes as provided in
Articles II, III, IV, V and VI, and any reference herein to the Notes shall be
deemed to be reference to such Tax Event Redemption Treasury Consideration, and
any reference herein to interest on the Notes shall be deemed to be a reference
to corresponding distributions on such Tax Event Redemption Treasury
Consideration. Upon the occurrence of a Tax Event Redemption, the Collateral
Agent shall be authorized to surrender the Notes in accordance with the
provisions of the Indenture.

      SECTION 6.4 Prepayment of Notes

      Upon the occurrence of a Prepayment Event prior to the Share Purchase Date
or the earlier successful remarketing of the Notes pursuant to Section 5.4 of
the Purchase Contract Agreement and the receipt in full by the Collateral Agent
of the principal amount of and accrued interest, if any, on the Pledged Notes,
the Collateral Agent will, at the written direction of the Company, purchase the
Prepayment Treasury Consideration and promptly remit the remaining portion, if
any, of the amounts received in respect of the principal of and accrued interest
on the Pledged Notes to the Purchase Contract Agent for payment to the Holders
of Normal Units. The Collateral Agent shall transfer the Prepayment Treasury
Consideration to the Collateral Account to secure the obligation of all Holders
of Normal Units to purchase Common Shares of the Company under the Purchase
Contracts constituting a part of such Normal Units, in substitution for the
Pledged Notes. Thereafter the Collateral Agent shall have such security
interests, rights and obligations with respect to the Prepayment Treasury
Consideration as it had in respect of the Pledged Notes as provided in Articles
II, III, IV, V and VI, and any reference herein to the Notes shall be deemed to
be reference to such Prepayment Treasury Consideration, and any reference herein
to interest on the Notes shall be deemed


                                      -17-
<PAGE>

to be a reference to corresponding distributions on such Prepayment Treasury
Consideration.

                                  ARTICLE VII

                   REPRESENTATIONS AND WARRANTIES; COVENANTS

      SECTION 7.1 Representations and Warranties of the Holders

      The Holders from time to time, acting through the Purchase Contract Agent
as their attorney-in-fact (it being understood that the Purchase Contract Agent
shall not be liable for any representation or warranty made by or on behalf of a
Holder), hereby represent and warrant to the Collateral Agent, which
representations and-warranties shall be deemed repeated on each day a Holder
Transfers Collateral that:

      (a) such Holder has the power to grant a security interest in and lien on
the Collateral;

      (b) such Holder is the sole beneficial owner of the Collateral and, in the
case of Collateral delivered in physical form, is the sole holder of such
Collateral and is the sole beneficial owner of, or has the right to Transfer,
the Collateral it Transfers to the Collateral Agent, free and clear of any
security interest, lien, encumbrance, call, liability to pay money or other
restriction other than the security interest and lien granted under Section 2.1;

      (c) upon the Transfer of the Collateral to the Collateral Account, the
Collateral Agent, for the benefit of the Company, will have a valid and
perfected first priority security interest therein (assuming that any central
clearing operation or any Intermediary or other entity not within the control of
the Holder involved in the Transfer of the Collateral, including the Collateral
Agent, gives the notices and takes the action required of it hereunder and under
applicable law for perfection of that interest and assuming the establishment
and exercise of control pursuant to Section 2.2); and

      (d) the execution and performance by the Holder of its obligations under
this Agreement will not result in the creation of any security interest, lien or
other encumbrance on the Collateral other than the security interest and lien
granted under Section 2.1 or violate any provision of any existing law or
regulation applicable to it or of any mortgage, charge, pledge, indenture,
contract or undertaking to which it is a party or which is binding on it or any
of its assets.

      SECTION 7.2 Representations and Warranties of the Collateral Agent,
Custodial Agent and Securities Intermediary

      The Collateral Agent, Custodial Agent and Securities Intermediary (each an
"Agent") hereby represents and warrants:


                                      -18-
<PAGE>

      (a) The Collateral Agent, Custodial Agent and Securities Intermediary is a
trust company duly incorporated and validly existing under the laws of
Massachusetts;

      (b) The execution, delivery and performance by the Collateral Agent, the
Custodial Agent and the Securities Intermediary of this Agreement have each been
duly authorized by all necessary corporate action on the part of each such
Agent; this Agreement has been duly executed and delivered by the Collateral
Agent, the Custodial Agent and the Securities Intermediary and constitutes a
valid and legally binding obligation of each of the Agents, enforceable against
such Agents in accordance with its terms, subject, as to enforcement, to
bankruptcy, insolvency, reorganization and other laws of general applicability
relating to or affecting creditors' rights and to general equity principles;

      (c) The execution, delivery and performance by the Collateral Agent, the
Custodial Agent and the Securities Intermediary of this Agreement do not violate
or constitute a breach of the Articles of Incorporation or By-Laws of any of
such Agents; and

      (d) No consent of any federal or state banking authority having regulatory
authority over the Agents in their individual capacity is required for the
execution and delivery of, or performance by the Agents of their respective
obligations under, this Agreement.

      SECTION 7.3 Covenants

      The Holders from time to time, acting through the Purchase Contract Agent
as their attorney-in-fact (it being understood that the Purchase Contract Agent
shall not be liable for any covenant made by or on behalf of a Holder), hereby
covenant to the Collateral Agent that for so long as the Collateral remains
subject to the Pledge:

      (a) neither the Purchase Contract Agent nor such Holders will create or
purport to create or allow to subsist any mortgage, charge, lien, pledge or any
other security interest whatsoever over the Collateral or any part of it other
than pursuant to this Agreement; and

      (b) neither the Purchase Contract Agent nor such Holders will sell or
otherwise dispose (or attempt to dispose) of the Collateral or any part of it
except for the beneficial interest therein, subject to the pledge hereunder,
transferred in connection with the Transfer of the Units.


                                      -19-
<PAGE>

                                  ARTICLE VII

                              THE COLLATERAL AGENT

      SECTION 8.1 Appointment, Powers and Immunities

      (a) The Collateral Agent shall act as agent for the Company hereunder with
such powers as are specifically vested in the Collateral Agent by the terms of
this Agreement, together with such other powers as are reasonably incidental
thereto. Each of the Collateral Agent, the Custodial Agent and the Securities
Intermediary:

      (i)   shall have no duties or responsibilities except those expressly set
            forth in this Agreement and no implied covenants or obligations
            shall be inferred from this Agreement against any of them, nor shall
            any of them be bound by the provisions of any agreement by any party
            hereto beyond the specific terms hereof;

      (ii)  shall not be responsible for any recitals contained in this
            Agreement, or in any certificate or other document referred to or
            provided for in, or received by it under, this Agreement, the Units
            or the Purchase Contract Agreement, or for the value, validity,
            effectiveness, genuineness, enforceability or sufficiency of this
            Agreement (other than as against the Collateral Agent), the Units or
            the Purchase Contract Agreement or any other document referred to or
            provided for herein or therein or for any failure by the Company or
            any other Person (except the Collateral Agent, the Custodial Agent
            or the Securities Intermediary, as the case may be) to perform any
            of its obligations hereunder or thereunder or, except as expressly
            required hereby, for the existence, validity, perfection, priority
            or maintenance of any security interest created hereunder,

      (iii) shall not be required to initiate or conduct any litigation or
            collection proceedings hereunder (except in the case of the
            Collateral Agent, pursuant to directions furnished under Section
            8.2, subject to Section 8.6);

      (iv)  shall not be responsible for any action taken or omitted to be taken
            by it hereunder or under any other document or instrument referred
            to or provided for herein or in connection herewith or therewith,
            except for its own negligence, bad faith or willful misconduct; and

      (v)   shall not be required to advise any party as to selling or
            retaining, or taking or refraining from taking any action with
            respect to, the Units or other property deposited hereunder.

Subject to the foregoing, during the term of this Agreement, the Collateral
Agent, in connection with the safekeeping and preservation of the Collateral
hereunder, shall use the same standard of care it applies for similar property
held for its own account.


                                      -20-
<PAGE>

      (b) No provision of this Agreement shall require the Collateral Agent, the
Custodial Agent or the Securities Intermediary to expend or risk its own funds
or otherwise incur any financial liability in the performance of any of its
duties hereunder. In no event shall the Collateral Agent, the Custodial Agent or
the Securities Intermediary be liable for any amount in excess of the value of
the Collateral or for any special, indirect, individual, consequential damages
or lost profits or loss of business, arising in connection with this Agreement.
Notwithstanding the foregoing, the Collateral Agent, the Custodial Agent, the
Purchase Contract Agent and Securities Intermediary, each in its individual
capacity, hereby waive any right of set-off, banker's lien, liens or perfection
rights as securities intermediary or any counterclaim with respect to any of the
Collateral. If the Company fails to pay the Collateral Agent, the Custodial
Agent and Securities Intermediary fees in connection with this Agreement, the
Collateral Agent, the Custodial Agent and Securities Intermediary retains the
right to set-off those fees from any funds to be transferred to the Company.

      (c) The Collateral Agent, Custodial Agent and Securities Intermediary
shall have no liability whatsoever for the action or inaction of any Clearing
Agency or any book-entry system thereof. In no event shall any Clearing Agency
or any book-entry system thereof be deemed an agent or subcustodian of the
Collateral Agent, Custodial Agent and Securities Intermediary.

      SECTION 8.2 Instructions of the Company.

      The Company shall have the right, by one or more instruments in writing
executed and delivered to the Collateral Agent, the Custodial Agent or the
Securities Intermediary, as the case may be, to direct the time, method and
place of conducting any proceeding for the realization of any right or remedy
available to the Collateral Agent, the Custodial Agent or the Securities
Intermediary, as the case may be, or of exercising any power conferred on the
Collateral Agent, the Custodial Agent or the Securities Intermediary, as the
case may be, or to direct the taking or refraining from taking of any action
authorized by this Agreement; provided that (i) such direction shall not
conflict with the provisions of any law or of this Agreement and (ii) the
Collateral Agent, the Custodial Agent and the Securities Intermediary shall each
receive indemnity reasonably satisfactory to it as provided herein. Nothing in
this Section 8.2 shall impair the right of the Collateral Agent in its
discretion to take any action or omit to take any action which it deems proper
and which is not inconsistent with such direction.

      SECTION 8.3 Reliance

      Each of the Securities Intermediary, the Custodial Agent and the
Collateral Agent shall be entitled conclusively to rely upon any certification,
order, judgment, opinion, notice or other communication (including, without
limitation, any thereof by telephone or facsimile) reasonably believed by it to
be genuine and correct and to have been signed or sent by or on behalf of the
proper Person or Persons (without being required to determine the correctness of
any fact stated therein), and upon advice and statements of legal


                                      -21-
<PAGE>

counsel and other experts selected by the Collateral Agent, the Custodial Agent
or the Securities Intermediary, as the case may be. As to any matters not
expressly provided for by this Agreement, the Collateral Agent, the Custodial
Agent and the Securities Intermediary shall in all cases be fully protected in
acting, or in refraining from acting, hereunder in accordance with instructions
given by the Company in accordance with this Agreement.

      SECTION 8.4 Rights in Other Capacities

      The Collateral Agent, the Custodial Agent and the Securities Intermediary
and their affiliates may (without having to account therefor to the Company)
accept deposits from, lend money to, make their investments in and generally
engage in any kind of banking, trust or other business with the Purchase
Contract Agent, any Holder of Units and any holder of Separate Notes (and any of
their respective subsidiaries or affiliates) as if it were not acting as the
Collateral Agent, the Custodial Agent or the Securities Intermediary, as the
case may be, and the Collateral Agent, the Custodial Agent and the Securities
Intermediary and their affiliates may accept fees and other consideration from
the Purchase Contract Agent, any Holder of Units or any holder of Separate Notes
without having to account for the same to the Company; provided that each of the
Securities Intermediary, the Custodial Agent and the Collateral Agent covenants
and agrees with the Company that it shall not accept, receive or permit there to
be created in favor of itself (and waives any right of set-off or banker's lien
with respect to) and shall take no affirmative action to permit there to be
created in favor of any other Person, any security interest, lien or other
encumbrance of any kind in or upon the Collateral and the Collateral shall not
be commingled with any other assets of any such Person.

      SECTION 8.5 Non-Reliance on Collateral Agent

      None of the Securities Intermediary, the Custodial Agent or the Collateral
Agent shall be required to keep itself informed as to the performance or
observance by the Purchase Contract Agent or any Holder of Units of this
Agreement, the Purchase Contract Agreement, the Units or any other document
referred to or provided for herein or therein or to inspect the properties or
books of the Purchase Contract Agent or any Holder of Units. The Collateral
Agent, the Custodial Agent and the Securities Intermediary shall not have any
duty or responsibility to provide the Company or the Remarketing Agent with any
credit or other information concerning the affairs, financial condition or
business of the Purchase Contract Agent, any Holder of Units or any holder of
Separate Notes (or any of their respective subsidiaries or affiliates) that may
come into the possession of the Collateral Agent, the Custodial Agent or the
Securities Intermediary or any of their respective affiliates.

      SECTION 8.6 Compensation and Indemnity

      The Company agrees:


                                      -22-
<PAGE>

      (a) to pay each of the Collateral Agent, the Custodial Agent and the
Securities Intermediary from time to time such compensation as shall be agreed
in writing between the Company and the Collateral Agent, Custodial Agent or the
Securities Intermediary, as the case may be, for all services rendered by each
of them hereunder and

      (b) to indemnify the Collateral Agent, the Custodial Agent and the
Securities Intermediary (which for purposes of this paragraph, in each case,
shall include its directors, officers, employees and agents) for, and to hold
each of them harmless from and against, any loss, liability or reasonable
out-of-pocket expense incurred without negligence, willful misconduct or bad
faith on its part, arising out of or in connection with the acceptance or
administration of its powers and duties under this Agreement, including the
reasonable out-of-pocket costs and expenses (including reasonable fees and
expenses of counsel) of defending itself against any claim or liability in
connection with the exercise or performance of such powers and duties or
collecting such amounts. The Collateral Agent, the Custodial Agent and the
Securities Intermediary shall each promptly notify the Company of any third
party claim which may give rise to the indemnity hereunder and give the Company
the opportunity to control the defense of such claim with counsel reasonably
satisfactory to the indemnified party and no such claim shall be settled without
the written consent of the Company, which consent shall not be unreasonably
withheld.

      SECTION 8.7 Failure to Act

      In the event of any ambiguity in the provisions of this Agreement or any
dispute between or conflicting claims by or among the parties hereto or any
other Person with respect to any funds or property deposited hereunder, the
Collateral Agent, Custodial Agent and the Securities Intermediary shall be
entitled, after prompt notice to the Company and the Purchase Contract Agent, at
its sole option, to refuse to comply with any and all claims, demands or
instructions with respect to such property or funds so long as such dispute or
conflict shall continue, and neither the Collateral Agent, Custodial Agent nor
the Securities Intermediary shall be or become liable in any way to any of the
parties hereto for its failure or refusal to comply with such conflicting
claims, demands or instructions. The Collateral Agent, Custodial Agent and the
Securities Intermediary shall be entitled to refuse to act until either (i) such
conflicting or adverse claims or demands shall have been finally determined by a
court of competent jurisdiction or settled by agreement between the conflicting
parties as evidenced in a writing, reasonably satisfactory to the Collateral
Agent, Custodial Agent or the Securities Intermediary, as the case may be, or
(ii) the Collateral Agent, the Custodial Agent or the Securities Intermediary,
as the case may be, shall have received security or an indemnity reasonably
satisfactory to the Collateral Agent, Custodial Agent or the Securities
Intermediary, as the case may be, sufficient to save the Collateral Agent,
Custodial Agent or the Securities Intermediary, as the case may be, harmless
from and against any and all loss, liability or reasonable out-of-pocket expense
which the Collateral Agent, Custodial Agent or the Securities Intermediary, as
the case may be, may incur by reason of its acting without bad faith, willful
misconduct or negligence. The Collateral Agent, Custodial Agent or the


                                      -23-
<PAGE>

Securities Intermediary may in addition elect to commence an interpleader action
or seek other judicial relief or orders as the Collateral Agent, Custodial Agent
or the Securities Intermediary, as the case may be, may deem necessary.
Notwithstanding anything contained herein to the contrary, neither the
Collateral Agent, Custodial Agent nor the Securities Intermediary shall be
required to take any action that is in its reasonable opinion contrary to law or
to the terms of this Agreement, or which would in its reasonable opinion subject
it or any of its officers, employees or directors to liability.

      SECTION 8.8 Resignation

      Subject to the appointment and acceptance of a successor Collateral Agent,
Custodial Agent or Securities Intermediary, as provided below, (a) the
Collateral Agent, Custodial Agent and the Securities Intermediary may resign at
any time by giving notice thereof to the Company and the Purchase Contract Agent
as attorney-in-fact for the Holders of Units, (b) the Collateral Agent,
Custodial Agent and the Securities Intermediary may be removed at any time by
the Company and (c) if the Collateral Agent, Custodial Agent or the Securities
Intermediary fails to perform any of its material obligations hereunder in any
material respect for a period of not less than 20 days after receiving written
notice of such failure by the Purchase Contract Agent and such failure shall be
continuing, the Collateral Agent, Custodial Agent or the Securities Intermediary
may be removed by the Purchase Contract Agent. The Purchase Contract Agent shall
promptly notify the Company of any removal of the Collateral Agent, the
Custodial Agent or the Securities Intermediary pursuant to clause (c) of the
immediately preceding sentence. Upon any such resignation or removal, the
Company shall have the right to appoint a successor Collateral Agent, Custodial
Agent or Securities Intermediary, as the case may be. If no successor Collateral
Agent, Custodial Agent or Securities Intermediary, as the case may be, shall
have been so appointed and shall have accepted such appointment within 30 days
after the retiring Collateral Agent's, Custodial Agent's or Securities
Intermediary's giving of notice of resignation or such removal, then the
retiring Collateral Agent, Custodial Agent or Securities Intermediary, as the
case may be, may at the Company's expense petition any court of competent
jurisdiction for the appointment of a successor Collateral Agent, Custodial
Agent or Securities Intermediary, as the case may be. Upon removal of the
Collateral Agent, Custodial Agent or Securities Intermediary, no fees paid to
the retiring Collateral Agent, Custodial Agent or Securities Intermediary
pursuant to Section 8.6(a) of this Agreement shall be refunded. Each of the
Collateral Agent, Custodial Agent and the Securities Intermediary shall be a
bank which has an office in New York, New York with a combined capital and
surplus of at least $50,000,000. Upon the acceptance of any appointment as
Collateral Agent, Custodial Agent or Securities Intermediary, as the case may
be, hereunder by a successor Collateral Agent, Custodial Agent or Securities
Intermediary, as the case may be, such successor shall thereupon succeed to and
become vested with all the rights, powers, privileges and duties of the retiring
Collateral Agent, Custodial Agent or Securities Intermediary, as the case may
be, and the retiring Collateral Agent, Custodial Agent or Securities
Intermediary, as the case may be, shall take all appropriate action to transfer
any money and property held by it hereunder (including the Collateral) to such
successor. The retiring


                                      -24-
<PAGE>

Collateral Agent, Custodial Agent or Securities Intermediary shall, upon such
succession, be discharged from its duties and obligations as Collateral Agent,
Custodial Agent or Securities Intermediary hereunder. After any retiring
Collateral Agent's, Custodial Agent's or Securities Intermediary's resignation
hereunder as Collateral Agent, Custodial Agent or Securities Intermediary, the
provisions of this Section 8.8 shall continue in effect for its benefit in
respect of any actions taken or omitted to be taken by it while it was acting as
the Collateral Agent, Custodial Agent or Securities Intermediary. Any
resignation or removal of the Collateral Agent hereunder shall be deemed for all
purposes of this Agreement as the simultaneous resignation or removal of the
Custodial Agent and the Securities Intermediary hereunder.

      Any corporation into which the Collateral Agent, the Custodial Agent or
the Securities Intermediary, in its individual capacity, may be merged or
converted or with which it may be consolidated, or any corporation resulting
from any merger, conversion or consolidation to which the Collateral Agent in
its individual capacity shall be a party, or any corporation to which
substantially all the corporate trust business of the Collateral Agent in its
individual capacity may be transferred, shall be the Collateral Agent, the
Custodial Agent, or the Securities Intermediary, as the case may be,
respectively, under this Agreement without further act.

      SECTION 8.9 Right to Appoint Agent or Advisor

      The Collateral Agent shall have the right to appoint agents or advisors in
connection with any of its duties hereunder, and the Collateral Agent shall not
be liable for any action taken or omitted by, or in reliance upon the advice of,
such agents or advisors selected in good faith. The appointment of agents (other
than legal counsel) pursuant to this Section 8.9 shall be subject to prior
consent of the Company, which consent shall not be unreasonably withheld.

      SECTION 8.10 Survival

      The provisions of this Article VIII shall survive termination of this
Agreement and the resignation or removal of the Collateral Agent, the Custodial
Agent or the Securities Intermediary.

      SECTION 8.11 Exculpation

      Anything in this Agreement to the contrary notwithstanding, in no event
shall any of the Collateral Agent, the Custodial Agent or the Securities
Intermediary or their officers, employees or agents be liable under this
Agreement to any third party for indirect, special, punitive or consequential
loss or damage of any kind whatsoever, including lost profits, whether or not
the likelihood of such loss or damage was known to the Collateral Agent, the
Custodial Agent or the Securities Intermediary, or any of them, incurred without
any act or deed that is found to be attributable to gross negligence, bad faith
or willful misconduct on the part of the Collateral Agent, the Custodial Agent
or the Securities Intermediary.


                                      -25-
<PAGE>

                                   ARTICLE IX

                                   AMENDMENT

      SECTION 9.1 Amendment Without Consent of Holders

      Without the consent of any Holders or the holders of any Separate Notes,
the Company, the Collateral Agent, the Custodial Agent, the Securities
Intermediary and the Purchase Contract Agent, at any time and from time to time,
may amend this Agreement, in form satisfactory to the Company, the Collateral
Agent, the Custodial Agent, the Securities Intermediary and the Purchase
Contract Agent, for any of the following purposes:

      (i)   to evidence the succession of another Person to the Company, and the
            assumption by any such successor of the covenants of the Company; or

      (ii)  to add to the covenants of the Company for the benefit of the
            Holders, or to surrender any right or power herein conferred upon
            the Company so long as such covenants or such surrender do not
            adversely affect the validity, perfection or priority of the
            security interests granted or created hereunder; or

      (iii) to evidence and provide for the acceptance of appointment hereunder
            by a successor Collateral Agent, Custodial Agent, Securities
            Intermediary or Purchase Contract Agent; or

      (iv)  to cure any ambiguity, to correct or supplement any provisions
            herein which may be inconsistent with any other such provisions
            herein, or to make any other provisions with respect to such matters
            or questions arising under this Agreement, provided such action
            shall not adversely affect the interests of the Holders.

      SECTION 9.2 Amendment with Consent of Holders

      With the consent of the Holders of not less than a majority of the
Purchase Contracts at the time outstanding, by Act of said Holders delivered to
the Company, the Purchase Contract Agent or the Collateral Agent, as the case
may be, the Company, when duly authorized, the Purchase Contract Agent, the
Collateral Agent, the Custodial Agent and the Securities Intermediary may amend
this Agreement for the purpose of modifying in any manner the provisions of this
Agreement or the rights of the Holders in respect of the Units; provided that no
such supplemental agreement shall, without the consent of the Holder of each
Outstanding Unit adversely affected thereby,

      (i)   change the amount or type of Collateral underlying a Unit (except
            for the rights of holders of Normal Units to substitute the Treasury
            Securities for the Pledged Notes or the Pledged Treasury
            Consideration, as the case may


                                      -26-
<PAGE>

            be, or the rights of Holders of Stripped Units to substitute Notes
            or the appropriate Treasury Consideration, as applicable, for the
            Pledged Treasury Securities), impair the right of the Holder of any
            Unit to receive distributions on the underlying Collateral or
            otherwise adversely affect the Holder's rights in or to such
            Collateral; or

      (ii)  otherwise effect any action that would require the consent of the
            Holder of each Outstanding Unit affected thereby pursuant to the
            Purchase Contract Agreement if such action were effected by an
            agreement supplemental thereto; or

      (iii) reduce the percentage of Purchase Contracts the consent of whose
            Holders is required for any such amendment.

It shall not be necessary for any Act of Holders under this Section to approve
the particular form of any proposed amendment, but it shall be sufficient if
such Act shall approve the substance thereof.

      SECTION 9.3 Execution of Amendments

      In executing any amendment permitted by this Article IX, the Collateral
Agent, the Custodial Agent, the Securities Intermediary and the Purchase
Contract Agent shall be entitled to receive and (subject to Section 8.1 hereof,
with respect to the Collateral Agent, and Section 7.1 of the Purchase Contract
Agreement, with respect to the Purchase Contract Agent) shall be fully protected
in relying upon, an Opinion of Counsel stating that the execution of such
amendment is authorized or permitted by this Agreement and that all conditions
precedent, if any, to the execution and delivery of such amendment have been
satisfied and, in the case of an amendment pursuant to Section 9.1, that such
amendment does not adversely affect the validity, perfection or priority of the
security interests granted or created hereunder.

      SECTION 9.4 Effect of Amendments

      Upon the execution of any amendment under this Article IX, this Agreement
shall be modified in accordance therewith, and such amendment shall form a part
of this Agreement for all purposes; and every Holder of Certificates theretofore
or thereafter authenticated, executed on behalf of the Holders and delivered
under the Purchase Contract Agreement shall be bound thereby.

      SECTION 9.5 Reference to Amendments

      Certificates authenticated, executed on behalf of the Holders and
delivered after the execution of any amendment pursuant to this Article IX may,
and shall if required by the Collateral Agent or the Purchase Contract Agent,
bear a notation in form approved by the Purchase Contract Agent as to any matter
provided for in such amendment. If the Company shall so determine, new
Certificates so modified as to conform, in the opinion


                                      -27-
<PAGE>

of the Purchase Contract Agent and the Company, to any such amendment may be
prepared and executed by the Company and authenticated, executed on behalf of
the Holders and delivered by the Purchase Contract Agent in accordance with the
Purchase Contract Agreement in exchange for outstanding Certificates.

                                   ARTICLE X

                                 MISCELLANEOUS

      SECTION 10.1 No Waiver

      No failure on the part of any party hereto or any of its agents to
exercise, and no course of dealing with respect to, and no delay in exercising,
any right, power or remedy hereunder shall operate as a waiver thereof; nor
shall any single or partial exercise by any party hereto or any of its agents of
any right, power or remedy hereunder preclude any other or further exercise
thereof or the exercise of any other right, power or remedy. The remedies herein
are cumulative and are not exclusive of any remedies provided by law.

      SECTION 10.2 GOVERNING LAW

      THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE
LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD TO CONFLICTS OF LAWS PRINCIPLES
THEREOF. Without limiting the foregoing, the above choice of law is expressly
agreed to by the Securities Intermediary, the Collateral Agent, the Custodial
Agent and the Holders from time to time acting through the Purchase Contract
Agent, as their attorney-in-fact, in connection with the establishment and
maintenance of the Collateral Account, which law, for purposes of the Code,
shall be deemed to be the law governing all Security Entitlements related
thereto. In addition, such parties agree that, for purposes of the Code, New
York shall be the Securities Intermediary's jurisdiction. The Company, the
Collateral Agent and the Holders from time to time of the Units, acting through
the Purchase Contract Agent as their attorney-in-fact, hereby submit to the
nonexclusive jurisdiction of the United States District Court for the Southern
District of New York and of any New York state court sitting in the Borough of
Manhattan in New York City for the purposes of all legal proceedings arising out
of or relating to this Agreement or the transactions contemplated hereby. The
Company, the Collateral Agent and the Holders from time to time of the Units,
acting through the Purchase Contract Agent as their attorney-in-fact,
irrevocably waive, to the fullest extent permitted by applicable law, any
objection which they may now or hereafter have to the laying of the venue of any
such proceeding brought in such a court and any claim that any such proceeding
brought in such a court has been brought in an inconvenient forum.


                                      -28-
<PAGE>

      SECTION 10.3 Notices

      Unless otherwise stated herein, all notices, requests, consents and other
communications provided for herein (including, without limitation, any
modification of, or waivers or consents under, this Agreement) shall be given or
made in writing (including, without limitation, by telecopy) delivered to the
intended recipient at the "Address for Notices" specified below its name on the
signature pages hereof or, as to any party, at such other address as shall be
designated by such party in a notice to the other parties. Except as otherwise
provided in this Agreement, all such communications shall be deemed to have been
duly given when personally delivered or, in the case of a mailed notice or
notice transmitted by telecopier, upon receipt, in each case given or addressed
as aforesaid.

      SECTION 10.4 Succeessors and Assigns

      This Agreement shall be binding upon and inure to the benefit of the
respective successors and assigns of the Company, the Collateral Agent, the
Custodial Agent, the Securities Intermediary and the Purchase Contract Agent,
and the Holders from time to time of the Units, by their acceptance of the same,
shall be deemed to have agreed to be bound by the provisions hereof and to have
ratified the agreement of, and the grant of the Pledge hereunder by, the
Purchase Contract Agent.

      SECTION 10.5 Counterparts

      This Agreement may be executed in any number of counterparts, all of which
taken together shall constitute one and the same instrument, and any of the
parties hereto may execute this Agreement by signing any such counterpart.

      SECTION 10.6 Severability

      If any provision hereof is invalid and unenforceable in any jurisdiction,
then, to the fullest extent permitted by law, (i) the other provisions hereof
shall remain in full force and effect in such jurisdiction and shall be
liberally construed in order to carry out the intentions of the parties hereto
as nearly as may be possible and (ii) the invalidity or unenforceability of any
provision hereof in any jurisdiction shall not affect the validity or
enforceability of such provision in any other jurisdiction.

      SECTION 10.7 Expenses, Etc.

      The Company agrees to reimburse the Collateral Agent, the Securities
Intermediary and the Custodial Agent for:

      (a) all reasonable out-of-pocket costs and all reasonable expenses of the
Collateral Agent, the Custodial Agent and the Securities Intermediary
(including, without limitation, the reasonable fees and expenses of counsel to
the Collateral Agent, the Custodial Agent and the Securities Intermediary), in
connection with (i) the negotiation,


                                      -29-
<PAGE>

preparation, execution and delivery or performance of this Agreement and (ii)
any modification, supplement or waiver of any of the terms of this Agreement;

      (b) all reasonable costs and expenses of the Collateral Agent (which for
purposes of this paragraph shall include its directors, officers, employees and
agents) (including, without limitation, reasonable fees and expenses of
counsel) in connection with (i) any enforcement or proceedings resulting or
incurred in connection with causing any Holder of Units to satisfy its
obligations under the Purchase Contracts forming a part of the Units and (ii)
the enforcement of this Section 10.7; and

      (c) all transfer, stamp, documentary or other similar taxes, assessments
or charges levied by any governmental or revenue authority in respect of this
Agreement or any other document referred to herein and all costs, expenses,
taxes, assessments and other charges incurred in connection with any filing,
registration, recording or perfection of any security interest contemplated
hereby.

      SECTION 10.8 Security Interest Absolute

      All rights of the Collateral Agent and security interests hereunder, and
all obligations of the Holders from time to time hereunder, shall be absolute
and unconditional irrespective of:

      (a) any lack of validity or enforceability of any provision of the
Purchase Contracts or the Units or any other agreement or instrument relating
thereto;

      (b) any change in the time, manner or place of payment of, or any other
term of, or any increase in the amount of, all or any of the obligations of
Holders of Units under the related Purchase Contracts, or any other amendment or
waiver of any term of, or any consent to any departure from any requirement of,
the Purchase Contract Agreement or any Purchase Contract or any other agreement
or instrument relating thereto; or

      (c) any other circumstance which might otherwise constitute a defense
available to, or discharge of, a borrower, a guarantor or a pledgor.

      SECTION 10.9 Waiver of Jury Trial

      EACH PARTY ACKNOWLEDGES AND AGREES THAT ANY CONTROVERSY WHICH MAY ARISE
UNDER THIS AGREEMENT IS LIKELY TO INVOLVE COMPLICATED AND DIFFICULT ISSUES, AND
THEREFORE IT HEREBY IRREVOCABLY AND UNCONDITIONALLY WAIVES ANY RIGHT IT MAY HAVE
TO A TRIAL BY JURY IN RESPECT OF ANY LITIGATION DIRECTLY OR INDIRECTLY ARISING
OUT OF OR RELATING TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY.


                                      -30-
<PAGE>

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

                                    PLATINUM UNDERWRITERS HOLDINGS, LTD.

                                    By: /s/ Jerome T. Fadden
                                       -----------------------------------------
                                    Name: Jerome T. Fadden
                                    Title: President and Chief Executive Officer

                                    Address for Notices:

                                    Platinum Underwriters Holdings, Ltd.
                                    Clarendon House, 2 Church Street
                                    Hamilton HM 11, Bermuda
                                    Attention: Secretary
                                    Telecopy:  (441) 295-4720
                                    Telephone: (441) 295-5950


                                    JPMorgan Chase Bank,
                                    as Purchase Contract Agent and
                                    as attorney-in-fact of the Holders
                                    from time to time of the Units

                                    By: /s/ J. Adamis
                                       -----------------------------------------
                                    Name: J. ADAMIS
                                    Title: Vice President

                                    Address for Notices:

                                    450 West 33rd Street, 15th Floor
                                    New York, New York 10001
                                    Attention: Institutional Trust Services
                                    Telecopy:  (212) 946-8154
                                    Telephone: (212) 946-3040


Pledge Agreement

<PAGE>

                         State Street Bank and Trust Company,
                         as Collateral Agent, Custodial Agent
                         and Securities Intermediary


                         By: /s/ E.C. Hammer
                            ---------------------------------------------------
                         Name: ELIZABETH C. HAMMER
                         Title: Vice President

                         Address for Notices:

                         c/o State Street Bank and Trust Company of Connecticut
                         Goodwin Square
                         225 Asylum Street
                         Hartford, CT 06103
                         Attention: Corporate Trust Administration
                         Telecopy:  860-244-1889
                         Telephone: 860-244-1813

<PAGE>

                                    EXHIBIT A

                       INSTRUCTION FROM PURCHASE CONTRACT
                           AGENT TO COLLATERAL AGENT

State Street Bank and Trust Company
c/o State Street Bank and Trust Company of Connecticut
Goodwin Square
225 Asylum Street
Hartford, CT 06103

Attention: Corporate Trust Administration

      Re:   Equity Security Units of Platinum Underwriters
            Holdings, Ltd. (the "Company")

      We hereby notify you in accordance with Section [4.1] [4.2] of the Pledge
Agreement, dated as of November 1, 2002, (the "Pledge Agreement") among the
Company, yourselves, as Collateral Agent, Custodial Agent and Securities
Intermediary and ourselves, as Purchase Contract Agent and as attorney-in-fact
for the holders of [Normal Units] [Stripped Units] from time to time, that the
holder of Units listed below (the "Holder") has elected to substitute [$_____
aggregate principal amount of Treasury Securities (CUSIP No. 912820BQ9)]
[$_______ aggregate principal amount of Notes or $_____ aggregate principal
amount of Treasury Consideration (CUSIP No. __________)] in exchange for the
related [Pledged Notes or Pledged Treasury Consideration] [Pledged Treasury
Securities] held by you in accordance with the Pledge Agreement and has
delivered to us a notice stating that the Holder has Transferred [Treasury
Securities] [Notes or the Treasury Consideration] to you, as Collateral Agent.
We hereby instruct you, upon receipt of such [Pledged Treasury Securities]
[Pledged Notes or Pledged Treasury Consideration], to release the [Notes or the
Treasury Consideration] [Treasury Securities] related to such [Normal Units]
[Stripped Units] to us in accordance with the Holder's instructions. Capitalized
terms used herein but not defined shall have the meaning set forth in the Pledge
Agreement.

Date: __________________

                                        JPMORGAN CHASE BANK,
                                        as Purchase Contract Agent


                                        By:_______________________________
                                           Name:
                                           Title:


                                      A-1
<PAGE>

Please print name and address of Registered Holder electing to substitute
[Treasury Securities] [Notes or Treasury Consideration] for the [Pledged Notes
or the Pledged Treasury Consideration] [Pledged Treasury Securities]:

Name:                                      Social Security or other Taxpayer
                                           Identification Number, if any:

Address:


                                      A-2
<PAGE>

                                   EXHIBTI B

                     INSTRUCTION TO PURCHASE CONTRACT AGENT

JPMorgan Chase Bank
  as Purchase Contract Agent
450 West 33rd Street, 15th Floor
New York, New York 10001

Attention: Institutional Trust Services

      Re:   Equity Security Units of Platinum Underwriters
            Holdings, Ltd. (the "Company")

The undersigned Holder hereby notifies you that it has delivered to State Street
Bank and Trust Company, as Collateral Agent, [$_______ aggregate principal
amount of Treasury Securities (CUSIP No. 912820BQ9)] [$_______ aggregate
principal amount of Notes or $_____ principal amount of Treasury Consideration
(CUSIP No. __________)] in exchange for the related [Pledged Notes or Pledged
Treasury Consideration] [Pledged Treasury Securities] held by the Collateral
Agent, in accordance with Section 4.1 of the Pledge Agreement, dated as of
November 1, 2002 (the "Pledge Agreement"), between you, the Company and the
Collateral Agent. The undersigned Holder hereby instructs you to instruct the
Collateral Agent to release to you on behalf of the undersigned Holder the
[Pledged Notes or the Pledged Treasury Consideration] [Pledged Treasury
Securities] related to such [Normal Units] [Stripped Units]. Capitalized terms
used herein but not defined shall have the meaning set forth in the Pledge
Agreement.

Date: _____________________     Signature:____________________________________

                                Signature Guarantee: _________________________

Please print name and address of Registered Holder:

Name:                           Social Security or other Taxpayer
                                Identification Number, if any:

Address:


                                      B-1
<PAGE>

                                    EXHIBIT C

              INSTRUCTION TO CUSTODIAL AGENT REGARDING REMARKETING

State Street Bank and Trust Company
c/o State Street Bank and Trust Company of Connecticut
Goodwin Square
225 Asylum Street
Hartford, CT 06103

Attention: Corporate Trust Administration

      Re:   Notes of Platinum Underwriters Finance, Inc.

The undersigned hereby notifies you in accordance with Section 4.5(d) of the
Pledge Agreement, dated as of November 1, 2002 (the "Pledge Agreement"), among
Platinum Underwriters Holdings, Ltd., yourselves, as Collateral Agent,
Securities Intermediary and Custodial Agent, and JPMorgan Chase Bank, as
Purchase Contract Agent and as attorney-in-fact for the Holders of Normal Units
and Stripped Units from time to time, that the undersigned elects to deliver on
the fourth Business Day immediately preceding the first day of the Remarketing
Period commencing on __________, 2005 $______ aggregate principal amount of
Notes for delivery to the Remarketing Agent for remarketing pursuant to Section
4.5(d) of the Pledge Agreement. The undersigned will, upon request of the
Remarketing Agent, execute and deliver any additional documents deemed by the
Remarketing Agent or by the Company to be necessary or desirable to complete the
sale, assignment and transfer of the Notes tendered hereby.

      The undersigned hereby instructs you, upon receipt of the proceeds of such
remarketing from the Remarketing Agent, net of amounts payable to the
Remarketing Agent in accordance with the Pledge Agreement, to deliver such
proceeds to the undersigned in accordance with the instructions indicated herein
under "A. Payment Instructions." The undersigned hereby instructs you, in the
event of [a/the Last] Failed Remarketing upon receipt of the Notes tendered
herewith from the Remarketing Agent, to deliver such Notes to the person(s) and
the address(es) indicated herein under "B. Delivery Instructions."

With this notice, the undersigned hereby (i) represents and warrants that the
undersigned has full power and authority to tender, sell, assign and transfer
the Notes tendered hereby and that the undersigned is the record owner of any
Notes tendered herewith in physical form or a participant in The Depository
Trust Company ("DTC") and the beneficial owner of any Notes tendered herewith by
book-entry transfer to your account at DTC and (ii) agrees to be bound by the
terms and conditions of Section 4.5(d)


                                      C-1
<PAGE>

of the Pledge Agreement. Capitalized terms used herein but not defined shall
have the meaning set forth in the Pledge Agreement.


Date: _____________________     Signature:____________________________________


                                Signature Guarantee: _________________________

Name:     ______________________________
          (Please Print)

Address:  ______________________________
          (Please Print)

Country:

Zip Code:

Telecopy (include country code if outside U.S.):

Telephone (include country code if outside U.S.):

(Tax Identification or Social Security Number):

A. PAYMENT INSTRUCTIONS

Proceeds of the remarketing should be paid by check in the name of the person(s)
set forth below and mailed to the address set forth below.

Name:     ______________________________
          (Please Print)

Address:  ______________________________
          (Please Print)

Zip Code:

Country:

Telecopy (include country code if outside U.S.):

Telephone (include country code if outside U.S.):

(Tax Identification or Social Security Number):


                                      C-2
<PAGE>

B. DELIVERY INSTRUCTIONS

In the event of [a/the Last] Failed Remarketing, Notes which are in physical
form should be delivered to the person(s) set forth below and mailed to the
address set forth below.

Name(s):    ______________________________
            (Please Print)

Address:    ______________________________
            (Please Print)

Zip Code:

Country:

Telecopy (include country code if outside U.S.):

Telephone (include country code if outside U.S.):

(Tax Identification or Social Security Number):

In the event of [a/the Last] Failed Remarketing, Notes which are in book-entry
form should be credited to the account at The Depository Trust Company set forth
below.

Name of Account Party:                                       DTC Account Number:


                                      C-3
<PAGE>

                                   EXHIBIT D

                    INSTRUCTION TO CUSTODIAL AGENT REGARDING
                          WITHDRAWAL FROM REMARKETING

State Street Bank and Trust Company
c/o State Street Bank and Trust Company of Connecticut
Goodwin Square
225 Asylum Street
Hartford, CT 06103

Attention: Corporate Trust Administration

      Re:   Notes of Platinum Underwriters Finance, Inc.

The undersigned hereby notifies you in accordance with Section 4.5(d) of the
Pledge Agreement, dated as of November 1, 2002 (the "Pledge Agreement"), among
Platinum Underwriters Holdings, Ltd., yourselves, as Collateral Agent,
Securities Intermediary and Custodial Agent, and JPMorgan Chase Bank, as
Purchase Contract Agent and as attorney-in-fact for the Holders of Normal Units
and Stripped Units from time to time, that the undersigned elects to withdraw
the $_____ aggregate principal amount of Notes delivered to the Custodial Agent
on ___________, 2005 for remarketing pursuant to Section 4.5(d) of the Pledge
Agreement. The undersigned hereby instructs you to return such Notes to the
undersigned in accordance with the undersigned's instructions. With this notice,
the undersigned hereby agrees to be bound by the terms and conditions of Section
4.5(d) of the Pledge Agreement. Capitalized terms used herein but not defined
shall have the meaning set forth in the Pledge Agreement.

Date: _____________________     Signature:____________________________________


                                Signature Guarantee: _________________________

Name(s):     ______________________________
             (Please Print)

Address:     ______________________________
             (Please Print)

Zip Code:

Country:

Telecopy (include country code if outside U.S.):

Telephone (include country code if outside U.S.):


                                      D-1
<PAGE>

(Tax Identification or Social Security Number):

A. DELIVERY INSTRUCTIONS

In the event of [a/the Last] Failed Remarketing, Notes which are in physical
form should be delivered to the person(s) set forth below and mailed to the
address set forth below.

Name(s):     ______________________________
             (Please Print)

Address:     ______________________________
             (Please Print)

Zip Code:

Country:

Telecopy (include country code if outside U.S.):

Telephone (include country code if outside U.S.):

(Tax Identification or Social Security Number):

In the event of [a/the Last] Failed Remarketing, Notes which are in book-entry
form should be credited to the account at The Depository Trust Company set forth
below.

Name of Account Party:                                       DTC Account Number:


                                      D-2