<PAGE>

                                                                    EXHIBIT 10.1

                                 TRUST AGREEMENT

                         Effective as of January 1, 2003

                                      among

                       PLATINUM UNDERWRITERS BERMUDA, LTD.

                                   as Grantor,

                     PLATINUM UNDERWRITERS REINSURANCE, INC.

                                 as Beneficiary,

                                       and

                       STATE STREET BANK AND TRUST COMPANY

                                   as Trustee

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                                TABLE OF CONTENTS

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Section 1.    Creation and Deposit of Assets to the Trust Account....................................   2

Section 2.    Withdrawal of Assets from the Trust Account............................................   3

Section 3.    Application of Assets..................................................................   4

Section 4.    Redemption, Investment and Substitution of Assets......................................   6

Section 5.    The Income Account.....................................................................   7

Section 6.    Right to Vote Assets...................................................................   7

Section 7.    Additional Rights and Duties of the Trustee............................................   7

Section 8.    The Trustee's Compensation, Expenses and Indemnification..............................   11

Section 9.    Resignation or Removal of the Trustee.................................................   12

Section 10.   Termination of the Trust Account......................................................   13

Section 11.   Definitions...........................................................................   14

Section 12.   Governing Law.........................................................................   15

Section 13.   Grantor's Tax Status..................................................................   16

Section 14.   Successors and Assigns................................................................   16

Section 15.   Severability..........................................................................   16

Section 16.   Entire Agreement......................................................................   16

Section 17.   Amendments............................................................................   17

Section 18.   Notices, etc..........................................................................   17

Section 19.   Headings..............................................................................   18

Section 20.   Counterparts..........................................................................   18

Section 21.   Insolvency of Grantor.................................................................   18

EXHIBIT A     70% Quota Share Retrocession Agreement

EXHIBIT B     List of Assets Deposited to the Trust Agreement
</TABLE>

                                       i

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                                 TRUST AGREEMENT

         TRUST AGREEMENT, effective as of January 1, 2003 (the "Agreement"),
among Platinum Underwriters Bermuda, Ltd., an insurance company limited by
shares under Bermuda law (the "Grantor"), Platinum Underwriters Reinsurance,
Inc., a Maryland-domiciled insurance company (the "Beneficiary"), and State
Street Bank and Trust Company, a Massachusetts trust company (the "Trustee")
(the Grantor, the Beneficiary and the Trustee are hereinafter each sometimes
referred to individually as a "Party" and collectively as the "Parties").

                               W I T N E S S E T H

         WHEREAS, the Grantor and the Beneficiary have entered into a Quota
Share Retrocession Agreement in the form set forth as Exhibit A hereto (the
"Retrocession Agreement");

         WHEREAS, the Beneficiary desires the Grantor to secure payments of all
amounts at any time and from time to time owing by the Grantor to the
Beneficiary under or in connection with the Retrocession Agreement;

         WHEREAS, the Grantor desires to transfer to the Trustee for deposit to
a trust account (the "Trust Account") assets in order to secure payments by the
Grantor under or in connection with the Retrocession Agreement;

         WHEREAS, the Trustee has agreed to act as trustee hereunder, and to
hold such assets in trust in the Trust Account for the sole use and benefit of
the Beneficiary; and

         WHEREAS, this Agreement is established for the sole use and benefit of
the Beneficiary and for the purposes of setting forth the duties and powers of
the Trustee with respect to the Trust Account and the relative rights and
obligations of the Parties hereto;

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         NOW, THEREFORE, for consideration of the premises and for other good
and valuable consideration, the receipt of which is hereby acknowledged, the
Parties hereby agree as follows:

SECTION 1.        CREATION AND DEPOSIT OF ASSETS TO THE TRUST ACCOUNT.

                  (a)      The Grantor shall establish and maintain the Trust
Account for the benefit of the Beneficiary as security for the obligations of
the Grantor under the Retrocession Agreement. The Grantor shall ensure that the
Trust Account shall be in a form reasonably satisfactory to the Beneficiary and,
except as otherwise expressly provided herein, shall comply in all material
respects with the requirements under Maryland Insurance Law applicable to trust
funds established for credit for reinsurance purposes. The Trustee shall
administer the Trust Account in its name as Trustee for the Beneficiary. The
Trust Account shall be subject to withdrawal by the Beneficiary solely as
provided herein.

                  (b)      The Grantor shall transfer to the Trustee, for
deposit to the Trust Account, the assets listed in Exhibit B hereto, and may
transfer to the Trustee, for deposit to the Trust Account, such other assets as
it may from time to time desire (all such assets actually received in the Trust
Account are herein referred to individually as an "Asset" and collectively as
the "Assets"). The Assets shall consist only of cash (United States legal
tender) and Qualifying Assets (as defined in Section 11 hereof).

                  (c)      The Grantor hereby represents and warrants that any
Asset transferred by the Grantor to the Trustee for deposit to the Trust Account
is and will be in such form that the Beneficiary or the Trustee on direction by
the Beneficiary, may negotiate, whenever necessary, any such Asset without
consent or signature from the Grantor or any other person or entity.

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                  (d)      The Grantor hereby represents and warrants that all
Assets transferred by the Grantor to the Trustee for deposit to the Trust
Account consist only of cash and Qualifying Assets.

                  (e)      The Grantor shall retain the investment discretion
with respect to the Assets in the Trust Account, provided, however, that all
Assets held in the Trust Account shall be invested consistently with the
Investment Guidelines (the "Investment Guidelines") attached to the
Discretionary Investment Advisory Agreement by and between Alliance Capital
Management L.P. and the Grantor.

                  (f)      Unless otherwise provided for in this Agreement, the
Trustee shall have no responsibility to determine (i) whether the Assets in the
Trust Account are sufficient to secure the Grantor's liabilities under the
Retrocession Agreement or (ii) whether they represent Qualifying Assets or (iii)
whether any investment of Assets in the Trust Account as directed by the Grantor
complies with the Investment Guidelines. Further, the Trustee shall have no
responsibility whatsoever to determine whether the Assets in the Trust Account
entitle either the Grantor or the Beneficiary to favorable or unfavorable tax,
accounting, or other treatment, consideration, evaluation or calculation under
any law, rule or regulation.

SECTION 2.        WITHDRAWAL OF ASSETS FROM THE TRUST ACCOUNT.

                  (a)      Without notice to the Grantor, the Beneficiary shall
have the right, at any time and from time to time, notwithstanding anything to
the contrary contained in the Retrocession Agreement, to withdraw from the
Trust Account, upon written notice to the Trustee (the "Withdrawal Notice"),
such Assets as are specified in such Withdrawal Notice. The Beneficiary need
present no statement or document in addition to a Withdrawal Notice in order to
withdraw any Assets; nor is said right of withdrawal or

                                       3

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any other provision of this Agreement subject to any conditions or
qualifications not contained in this Agreement.

                  (b)      Upon receipt of a Withdrawal Notice, the Trustee
shall promptly take the steps necessary to transfer absolutely all right, title
and interest in the Assets specified in such Withdrawal Notice and shall deliver
physical custody of such assets to or for the account of the Beneficiary. In the
event that the Trustee must sell an investment in order to comply with the
Withdrawal Notice, the Trustee shall not be liable for any loss or penalty
associated with such investment, except to the extent such loss or penalty
arises from the Trustee's negligence, willful misconduct or lack of good faith,
or failure to comply with the Withdrawal Notice.

                  (c)      Subject to paragraph (a) of this Section 2 and to
Section 4 of this Agreement, in the absence of a Withdrawal Notice, the Trustee
shall allow no substitution or withdrawal of any Asset from the Trust Account.

                  (d)      The Trustee shall have no responsibility whatsoever
to determine that any Assets withdrawn from the Trust Account pursuant to this
Section 2 are withdrawn in compliance with the Retrocession Agreement, or will
be used and applied in the manner contemplated by Section 3 of this Agreement.

SECTION 3.        APPLICATION OF ASSETS.

                  (a)      The Beneficiary hereby covenants to the Grantor that
it shall use and apply any withdrawn Assets, without diminution because of the
insolvency of the Beneficiary or the Grantor, for the following purposes only:

                  (i)      to pay or reimburse the Beneficiary for the Grantor's
share under the Retrocession Agreement regarding any losses and allocated loss
expenses paid by the Beneficiary but not recovered from the Grantor, or unearned
premiums due to the Beneficiary or for other amounts due to the

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Beneficiary, if not otherwise paid by the Grantor in accordance with the terms
of the Retrocession Agreement;

                  (ii)     to make payment to the Grantor of any amounts held in
the Trust Account that exceed 100% of the actual amount required to fund the
Grantor's entire Obligations (as defined in Section 11 hereof), and

                  (iii)    where the Beneficiary has received a Termination
Notice (as defined in Section 10 hereof) pursuant to Section 10 of this
Agreement and where all or a portion of the Grantor's Obligations remain
unliquidated and undischarged ten days prior to the Termination Date (as defined
in Section 10 hereof), to withdraw amounts equal to such Obligations and deposit
such amounts in a separate account, in the name of the Beneficiary, in any
Qualified United States Financial Institution (as defined in Section 11 hereof),
apart from its other assets, in trust for the uses and purposes specified in
subparagraphs (i) and (ii) of this Section as may remain executory after such
withdrawal and for any period after such Termination Date. For the purposes of
this subparagraph (iii), the phrase "the Trust Account" in subparagraph (ii) of
this Section shall be deemed to read "the separate account" established pursuant
to this subparagraph (iii).

                  (b)      In the event Assets are withdrawn and held by the
Beneficiary prior to being applied pursuant to this Section 3, such Assets shall
be deposited in an interest bearing account to be held separate from the
Beneficiary's other assets and interest thereon shall accrue to the benefit of
the Grantor.

                  (c)      For purposes of this Section 3, all Assets shall be
valued at their current fair market value.

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SECTION 4.        REDEMPTION, INVESTMENT AND SUBSTITUTION OF ASSETS.

                  (a)      The Trustee shall surrender for payment all maturing
Assets and all Assets called for redemption (and provide written notice to the
Beneficiary to that effect) and deposit the principal amount of the proceeds of
any such payment to the Trust Account.

                  (b)      From time to-time, at the written order and direction
of the Grantor, any instruction or order concerning investments being referred
to herein as an "Investment Order", the Trustee shall invest Assets in the Trust
Account in Qualifying Assets.

                  (c)      From time to time, subject to the prior written
approval of the Beneficiary, the Grantor may direct the Trustee to substitute
Qualifying Assets for other Qualifying Assets held in the Trust Account at such
time. The Trustee shall have no responsibility whatsoever to determine the value
of such substituted securities or that such substituted securities constitute
Qualifying Assets.

                  (d)      The Trustee shall not allow any substitutions or
withdrawals of assets from the Trust Account, except on (i) written instructions
from the Beneficiary, or (ii) a call on or the maturity of any trust Asset if
the Trustee provides written notice to the Beneficiary and pays the proceeds
from the Asset into the Trust Account.

                  (e)      All investments and substitutions of securities
referred to in paragraphs (b) and (c) of this Section 4 must constitute
Qualifying Assets, as defined in Section 11 of this Agreement. The Trustee shall
have no responsibility whatsoever to determine that any Assets in the Trust
Account are or continue to be Qualifying Assets. The Trustee shall execute
Investment Orders and settle securities transactions by itself or by means of an
agent or broker. The Trustee shall not be responsible for any act or

                                       6

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omission, or for the solvency, of any such agent or broker unless said act or
omission is the result, in whole or in part, of the Trustee's negligence,
willful misconduct or lack of good faith.

                  (f)      Any loss incurred from any investment pursuant to the
terms of this Section 4 shall be borne exclusively by the Trust Account. The
Trustee shall not be liable for any loss due to changes in market rates or
penalties for early redemption.

SECTION 5.        THE INCOME ACCOUNT.

         All payments of interest and dividends actually received in respect of
Assets in the Trust Account shall be deposited by the Trustee, in a separate
account (the "Income Account") established and maintained by the Grantor at an
office of the Trustee in the United States. The Grantor shall have the right to
withdraw funds from the Income Account at any time. The Grantor shall provide
the Trustee with the appropriate wiring instructions for such withdrawals from
the Income Account.

SECTION 6.        RIGHT TO VOTE ASSETS.

         The Trustee shall forward all annual and interim stockholder reports
and all proxies and proxy materials relating to the Assets in the Trust Account
to the Grantor. The Grantor shall have the full and unqualified right to vote
any Assets in the Trust Account.

SECTION 7.        ADDITIONAL RIGHTS AND DUTIES OF THE TRUSTEE.

                  (a)      The Trustee shall receive Assets and hold the Assets
in a safe place.

                  (b)      The Trustee shall provide to the Grantor and the
Beneficiary a statement of all Assets in the Trust Account on its inception and
at the end of each calendar quarter.

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                  (c)      The Trustee shall notify the Grantor and the
Beneficiary, within 10 days, of any deposits to or withdrawals from the Trust
Account.

                  (d)      The Trustee shall hold the Assets in the Trust
Account at the Trustee's office in the United States.

                  (e)      The Trustee may deposit any Assets in the Trust
Account in a book-entry account maintained at the appropriate Federal Reserve
Bank and in depositories such as the Depository Trust Company. Assets may be
held in the name of a nominee maintained by the Trustee or by any such
depository.

                  (f)      Subject to paragraph (g) of this Section 7, the
Trustee shall accept and open all mail directed to the Grantor or the
Beneficiary in care of the Trustee.

                  (g)      Upon the request of the Grantor or the Beneficiary,
the Trustee shall promptly permit the Grantor or the Beneficiary, their
respective agents, employees or independent auditors to examine, audit, excerpt,
transcribe and copy, during the Trustee's normal business hours, any books,
documents, papers and records relating to the Trust Account or the Assets.

                  (h)      The Trustee is authorized to follow and rely upon all
instructions given by applicable officers named in incumbency certificates
furnished to the Trustee from time to time by the Grantor and Beneficiary,
respectively, and by attorneys-in-fact acting under written authority furnished
to the Trustee by the Grantor or the Beneficiary, including, without limitation,
instructions given by letter, facsimile transmission, telegram, teletype,
cablegram or electronic media other than e-mail, if the Trustee believes such
instructions to be genuine and to have been signed, sent or presented by the
proper party or parties. Such instructions may also be in a tested communication
utilizing

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access codes effected between electro-mechanical or electronic devices. The
Trustee shall not incur any liability to anyone resulting from actions taken by
the Trustee in reliance in good faith on such instructions. The Trustee shall
not incur any liability in executing instructions(i) from an attorney-in-fact or
(ii) from any officer of the Grantor of the Beneficiary named in an incumbency
certificate delivered hereunder prior to receipt by it of a more current
certificate.

                  (i)      The duties and obligations of the Trustee shall only
be such as are specifically set forth in this Agreement, as it may from time to
time be amended, and no implied duties or obligations shall be read into this
Agreement against the Trustee. The Trustee shall not be charged with knowledge
of any document, instrument or agreement, other than this Agreement. The Trustee
shall only be liable for its own negligence, willful misconduct or lack of good
faith.

                  (j)      No provision of this Agreement shall require the
Trustee to take any action which, in the Trustee's reasonable judgment, would
result in any violation of this Agreement or any provision of law or, following
written advice from counsel, expose the Trustee to personal liability.

                  (k)      The Trustee may confer with counsel of its own choice
in relation to matters arising under this Agreement and shall have full and
complete authorization from the other Parties hereunder for any action taken or
suffered by it under this Agreement or under any transaction contemplated hereby
in good faith and in accordance with the opinion of such counsel.

                  (l)      The invasion of the trust corpus to pay compensation
to, or reimburse the expense of, the Trustee is hereby prohibited.

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                  (m)      The Trustee shall deliver to the Beneficiary written
notice of termination at least 30 days before termination of the Trust Account.

                  (n)      Except as may arise from the Trustee's own negligence
or willful misconduct or lack of good faith, the Trustee shall be without
liability for any loss, liability, claim or expense resulting from or caused by
events or circumstances beyond the reasonable control of the Trustee, including,
without limitation, the interruption, suspension or restriction of trading on or
the closure of any securities markets, power or other mechanical or
technological failures or interruptions, or computer viruses or communications
disruptions, work stoppages, natural disasters or other similar events or acts,
delays or inability to perform its duties due to any disorder in market
infrastructure with respect to any particular security or changes to any
provision of any present or future law or regulation or order of the United
States of America, or any state thereof, or any other country, or political
subdivision thereof or any court of competent jurisdiction.

                  (o)      The Trustee, in incurring any debt, liability or
obligation, or in taking or omitting to take any action for or in connection
with the Trust, is and shall be deemed to be acting solely as a trustee, and not
in an individual capacity. The Trustee shall assume no responsibility and shall
not be held to any personal liability whatsoever in tort, contract, or otherwise
for any action taken or omitted pursuant to this Agreement. In the event that
the Grantor or the Beneficiary enters into any agreement or arrangement of any
kind with any third party with respect to all or any part of the Trust Account,
the Grantor or the Beneficiary, as appropriate, shall ensure that the agreement
or arrangement shall pose no risk of personal liability to the Trustee.

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SECTION 8.        THE TRUSTEE'S COMPENSATION, EXPENSES AND INDEMNIFICATION.

                  (a)      The Grantor shall pay the Trustee, as compensation
for its services under this Agreement, a fee at rates determined by the Trustee
and agreed to by the Grantor, from time to time and communicated in writing to
the Grantor. The Grantor shall pay or reimburse the Trustee for all of the
Trustee's reasonable expenses and disbursements in connection with its duties
under this Agreement (including attorney's fees and expenses), except any such
expense, or disbursement as may arise from the Trustee's negligence, willful
misconduct or lack of good faith. The Grantor shall indemnify, defend and save
harmless the Trustee from all loss or expense (including the fees and expenses
of in house or outside counsel) arising out of or in connection with (i) its
execution and performance of this Agreement, except to the extent that such
loss, liability or expense is due to the negligence, willful misconduct or lack
of good faith of the Trustee, or (ii) its following any instructions or other
directions from the Grantor, except to the extent that its following any such
instructions or direction is expressly forbidden by the terms hereof. In no
event shall the Trustee be liable for special, indirect or consequential loss or
damage of any kind whatsoever. The Grantor hereby acknowledges that the
foregoing indemnities shall survive the resignation of the Trustee or the
termination of this Agreement and hereby grants the Trustee a lien, right of
set-off and security interest in the funds in the Income Account for the payment
of any claim for compensation, reimbursement or indemnity hereunder.

                  (b)      No Assets shall be withdrawn from the Trust Account
or used in any manner for paying compensation to, or reimbursement or
indemnification of, the Trustee.

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SECTION 9.        RESIGNATION OR REMOVAL OF THE TRUSTEE.

                  (a)      The Trustee may resign at any time by giving not less
than ninety (90) days' written notice thereof to the Beneficiary and to the
Grantor, such resignation to become effective only on the acceptance of
appointment by a successor trustee and the transfer to such successor trustee of
all Assets in the Trust Account in accordance with paragraph (b) of this Section
9.

                  (b)      Upon receipt of the Trustee's notice of resignation,
the Grantor and the Beneficiary shall appoint a successor trustee. Any successor
trustee shall be a Qualified United States Financial Institution and shall not
be a Parent, a Subsidiary or an Affiliate of the Grantor or the Beneficiary.
Upon the acceptance of the appointment as trustee hereunder by a successor
trustee and the transfer to such successor trustee of all Assets in the Trust
Account, the resignation of the Trustee shall become effective. Thereupon, such
successor trustee shall succeed to and become vested with all the rights,
powers, privileges and duties of the Trustee, and the Trustee shall be
discharged from any future duties and obligations under this Agreement, but the
Trustee shall continue after its resignation to be entitled to the benefits of
the indemnities provided herein for the Trustee. If a successor has not been
appointed within ninety (90) days of the Trustee's notice of resignation, the
Trustee may apply to a court of competent jurisdiction to have a successor
trustee appointed.

                  (c)      The Grantor may remove the Trustee at any time by
giving not less than ninety (90) days' written notice thereof to the Beneficiary
and to the Trustee, such removal to become effective only on the acceptance of
appointment by a successor trustee and the transfer to such successor trustee of
all Assets in the Trust Account in accordance with paragraph (d) of this Section
9.

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                  (d)      Upon receipt of the Grantor's notice of removal, the
Grantor and the Beneficiary shall appoint a successor trustee. Any successor
trustee shall be a Qualified United States Financial Institution and shall not
be a Parent, a Subsidiary or an Affiliate of the Grantor or the Beneficiary.
Upon the acceptance of the appointment as trustee hereunder by a successor
trustee and the transfer to such successor trustee of all Assets in the Trust
Account, the removal of the Trustee shall become effective. Thereupon, such
successor trustee shall succeed to and become vested with all the rights,
powers, privileges and duties of the Trustee, and the Trustee shall be
discharged from any future duties and obligations under this Agreement, but the
Trustee shall continue after its removal to be entitled to the benefits of the
indemnities provided herein for the Trustee.

SECTION 10.       TERMINATION OF THE TRUST ACCOUNT.

                  (a)      The Trust Account and this Agreement, except as
provided in Section 1(e) hereof and except for the indemnities provided herein,
may be terminated only after (i) the Grantor and the Beneficiary have given the
Trustee written notice of their intention to terminate the Trust Account (the
"Notice of Intention"), and (ii) the Trustee has given the Grantor and the
Beneficiary the written notice specified in paragraph (b) of this Section 10.
The Notice of Intention shall specify the date on which the parties intend the
Trust Account to terminate (the "Proposed Date").

                  (b)      Within ten Business Days following receipt by the
Trustee of the Notice of Intention, the Trustee shall give written notification
(the "Termination Notice") to the Beneficiary and the Grantor of the date (the
"Termination Date") on which the Trust Account shall terminate. The Termination
Date shall be (a) the Proposed Date (or if not a Business Day, the next Business
Day thereafter), if the Proposed Date is at least 30 days but no more than 45
days subsequent to the date the Termination Notice is given;

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(b) 30 days subsequent to the date the Termination Notice is given (or if not a
Business Day, the next Business Day thereafter), if the Proposed Date is fewer
than 30 days subsequent to the date the Termination Notice is given; or (c) 45
days subsequent to the date the Termination Notice is given (or if not a
Business Day, the next Business Day thereafter), if the Proposed Date is more
than 45 days subsequent to the date the Termination Notice is given.

                  (c)      On the Termination Date, upon receipt of written
approval of the Beneficiary, the Trustee shall transfer to the Grantor any
Assets remaining in the Trust Account, at which time all liability of the
Trustee with respect to such Assets shall cease.

SECTION 11.       DEFINITIONS.

         Except as the context shall otherwise require, the following terms
shall have the following meanings for all purposes of this Agreement (the
definitions to be applicable to both the singular and the plural forms of each
term defined if both such forms of such term are used in this Agreement):

         The term "Affiliate" with respect to any corporation shall mean a
corporation which directly, or indirectly through one of more intermediaries,
controls or is controlled by, or is under common control with, such corporation.

         The term "control" (including the related terms "controlled by" and
"under common control with") shall mean the ownership, directly or indirectly,
of more than fifty percent (50%) of the voting stock of a corporation.

         The term "Business Day" shall mean any day on which the offices of the
Trustee in Boston, Massachusetts are open for business.

         The term "Expenses" shall mean the Trustee's reasonable expenses and
disbursements in connection with its duties under this Agreement (including
reasonable

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attorney's fees and expenses), not including any such expense or disbursement as
may arise from the Trustee's negligence, willful misconduct or lack of good
faith.

         The term "Obligations" shall mean, with respect to the Retrocession
Agreement, (a) reinsured losses and allocated loss expenses paid by the
Beneficiary, but not recovered from the Grantor, (b) reserves for reinsured
losses reported and outstanding, (c) reserves for reinsured losses incurred but
not reported, and (d) reserves for allocated reinsured loss expenses and
unearned premiums.

         The term "Parent" shall mean an institution that, directly or
indirectly, controls another institution.

         The term "person" shall mean and include an individual, a corporation,
a partnership, an association, a trust, an unincorporated organization or a
government or political subdivision thereof.

         The term "Qualified United States Financial Institution" shall have the
meaning provided in COMAR 31.05.08.08.B(3)(a) - (c) of the Code of Maryland
Regulations.

         The term "Qualifying Assets" shall mean and include any security listed
by the Securities Valuation Office of the National Association of Insurance
Commissioners and qualifying as an admitted asset under applicable Maryland law.

         The term "Subsidiary" shall mean an institution controlled, directly or
indirectly, by another institution.

SECTION 12.       GOVERNING LAW.

         This Agreement shall be governed by and construed in accordance with
the laws of the Commonwealth of Massachusetts without regard to its choice of
laws principles.

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SECTION 13.       GRANTOR'S TAX STATUS.

         The Grantor shall provide the Trustee with a certificate of foreign
status on Form W-8 or its tax identification number as assigned by the Internal
Revenue Service, as applicable.

SECTION 14.       SUCCESSORS AND ASSIGNS.

         No Party may assign this Agreement or any of its obligations hereunder
without the prior written consent of the other Parties; provided, however, that
this Agreement shall inure to the benefit of and bind those who, by operation of
law, become successors to the Parties, including, without limitation, any
liquidator, rehabilitator, receiver or conservator and any successor merged or
consolidated entity and provided further that, in the case of the Trustee, the
successor trustee is eligible to be a trustee under the terms hereof.

SECTION 15.       SEVERABILITY.

         In the event that any provision of this Agreement shall be declared
invalid or unenforceable by any regulatory body or court having jurisdiction,
such invalidity or unenforceability shall not affect the validity or
enforceability of the remaining portions of this Agreement.

SECTION 16.       ENTIRE AGREEMENT.

         This Agreement constitutes the entire agreement among the Parties, and
there are no understandings or agreement, conditions or qualifications relative
to this Agreement which are not fully expressed in this Agreement.

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SECTION 17.       AMENDMENTS.

         This Agreement may be modified or otherwise amended, and the observance
of any term of this Agreement may be waived, if such modification, amendment or
waiver is in writing and signed by all of the Parties.

SECTION 18.       NOTICES

         Unless otherwise provided in this Agreement, all notices, directions,
requests, demands, acknowledgments and other communications required or
permitted to be given or made under the terms hereof shall be in writing and
shall be deemed to have been duly given or made on the date received when
addressed as follows:

If to the Grantor:         Platinum Underwriters Bermuda, Ltd.
                           Belvedere Building
                           69 Pitts Bay Road
                           Pembroke HM 08
                           Bermuda
                           Attention:  Chief Operating Officer
                           Fax No.:  (441) 292-4720

If to the Beneficiary:     Platinum Underwriters Reinsurance, Inc.
                           195 Broadway
                           New York, New York 10007
                           Attention:  Chief Financial Officer
                           Fax No.:  (212) 238-9202

If to the Trustee:         State Street Bank and Trust Company
                           801 Pennsylvania Avenue
                           Kansas City, Missouri 64105
                           Attention:  Vice President, Insurance Services
                           Fax No.:  (816) 871-9210

         Each Party may from time to time designate a different address for
notices, directions, requests, demands, acknowledgments and other communications
by giving written notice of such change to the other Parties. All notices,
directions, requests, demands, acknowledgments and other communications relating
to the Beneficiary's

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approval of the Grantor's authorization to substitute Assets and to the
termination of the Trust Account shall be in writing.

SECTION 19.       HEADINGS.

         The headings of the Sections and the Table of Contents have been
inserted for convenience of reference only, and shall not be deemed to
constitute a part of this Agreement.

SECTION 20.       COUNTERPARTS.

         This Agreement may be executed in any number of counterparts, each of
which when so executed and delivered shall constitute an original, but such
counterparts together shall constitute one and the same Agreement.

SECTION 21.       INSOLVENCY OF GRANTOR.

                  (a)      Notwithstanding any other provision in this
Agreement, if the Grantor has been declared insolvent or placed into
receivership, rehabilitation, liquidation, or similar proceedings under the laws
of Bermuda, the Trustee shall comply with any order of the regulatory authority
with oversight over the Trust Account or court of competent jurisdiction
directing the Trustee to transfer to such regulatory authority or other
designated receiver all of the assets in the Trust Account.

                  (b)      The assets so transferred shall be applied in
accordance with the priority statutes of the state in which the Trust Account is
established applicable to the assets of insurance companies in liquidation.

                  (c)      If the regulatory authority with oversight over the
Trust Account determines that the assets held in the Trust Account or any part
of the assets are not necessary to satisfy the claims of the Beneficiary, the
assets or any part of the assets shall be returned to the Trustee for
distribution in accordance with this Agreement.

                                       18

<PAGE>

         IN WITNESS WHEREOF, the Parties hereto have caused this Agreement to be
executed and delivered by their respective officers thereunto duly authorized as
of the date first above written.

                                    PLATINUM UNDERWRITERS BERMUDA, LTD.
                                    As Grantor

                                    By: /s/  Bart Hedges
                                        ----------------
                                    Title: Chief Operating Officer

                                    PLATINUM UNDERWRITERS REINSURANCE, INC.
                                    As Beneficiary

                                    By: /s/ Michael D. Price
                                        --------------------
                                    Title: President and Chief Underwriting
                                           Officer

                                            and

                                    STATE STREET BANK AND TRUST COMPANY
                                    As Trustee

                                    By: /s/  Kenneth A. Bergeron
                                        ------------------------
                                    Title: Senior Vice President

                                       19

<PAGE>

                                    EXHIBIT A

                       Quota Share Retrocession Agreement
                            Dated as of May 13, 2003

                                    Ex. A-1

<PAGE>

                                    EXHIBIT B

                            [List of Assets Deposited
                              to the Trust Account]

                                    Ex. B-1