Document:

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                                                                   Exhibit 10.92

                                 ADDENDUM NO. 1

                                     to the

                       QUOTA SHARE RETROCESSION AGREEMENT

                                 BY AND BETWEEN

                       PLATINUM UNDERWRITERS BERMUDA, LTD.

                                       and

                     PLATINUM UNDERWRITERS REINSURANCE, INC.

                            DATED AS OF MAY 13, 2003

IT IS HEREBY MUTUALLY AGREED that effective October 1, 2003, this Quota Share
Retrocession Agreement ("Agreement"), made by and between Platinum Underwriters
Bermuda, Ltd., a Bermuda-domiciled insurance company (the "Retrocessionaire"),
and Platinum Underwriters Reinsurance, Inc. a Maryland-domiciled insurance
company (the "Retrocedant"), is amended as follows:

         1. Article 1 - BUSINESS COVERED

With respect to business classified by the Retrocedant as Property Catastrophe
and underwritten out of its New York office, the Retrocedant hereby obligates
itself to retrocede to the Retrocessionaire and the Retrocessionaire hereby
obligates itself to accept a sixty seven percent (67%) quota share of the
reinsurance and retrocession contracts underwritten by Retrocedant on or after
the Effective Date other than reinsurance contracts retroceded to Retrocedant by
any subsidiary or affiliate of The St. Paul Companies, Inc. (the "NY Property
Catastrophe Reinsurance Contracts").

With respect to all business underwritten by the Retrocedant except for NY
Property Catastrophe Reinsurance Contracts, the Retrocedant hereby obligates
itself to retrocede to the Retrocessionaire and the Retrocessionaire hereby
obligates itself to accept a ninety percent (90%) quota share of the reinsurance
and retrocession contracts underwritten by Retrocedant on or after the Effective
Date of the Agreement other than reinsurance contracts retroceded to Retrocedant
by any subsidiary or affiliate of The St. Paul Companies, Inc. (the "Non NY
Catastrophe Reinsurance Contracts"). The NY Property Catastrophe Reinsurance
Contracts and the Non NY Catastrophe Reinsurance Contracts may be collectively
referred to herein as the "Reinsurance Contracts."

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         2. Article 4 - PREMIUMS

With regards to the Non NY Catastrophe Reinsurance Contracts, the Retrocedant
shall retrocede to the Retrocessionaire an amount equal to ninety percent (90%)
of the Net Premium earned under the Non NY Catastrophe Reinsurance Contracts on
or after the effective date of this Addendum.

With regards to the NY Property Catastrophe Reinsurance Contracts, the
Retrocedant shall retrocede to the Retrocessionaire an amount equal to
sixty-seven (67%) of Net Premium due under the NY Property Catastrophe
Reinsurance Contracts.

Net Premium shall be defined as the Gross Net Premium less (i) one hundred
percent (100%) of the actual expenses incurred by Retrocedant in acquiring the
respective Reinsurance Contracts, including all commissions and brokerage, and
(ii) seven percent (7%) of the Gross Net Premium due under the respective
Reinsurance Contracts.

For purposes of this Agreement, the term "Gross Net Premium" is the amount equal
to (i) the gross premium ceded to Retrocedant under the respective Reinsurance
Contracts less (ii) return premium paid or payable by the Retrocedant under the
respective Reinsurance Contracts, and (iii) premiums paid or payable by the
Retrocedant for inuring reinsurance as described in Article 7 hereof.

On the effective date of this Addendum, Retrocedant shall pay to the account of
the Retrocessionaire an aggregate amount equal to twenty percent (20%) of the
gross carrying value on the books of the Retrocedant as of September 30, 2003,
of the aggregate of all loss reserves relating to the Non NY Catastrophe
Reinsurance Contracts. Loss reserves shall consist of loss and loss adjustment
expense reserves, including incurred but not reported loss and loss adjustment
expenses. For purposes of clarity, this transfer of twenty percent of the loss
reserves is intended to increase the total ceded amount of outstanding balances
due under this Agreement to ninety percent (90%).

All other terms and conditions of this Agreement shall remain unchanged.

         IN WITNESS WHEREOF, the parties hereto have caused this Addendum to be
executed by their duly authorized representatives this 31st day of December,
2003.

                            Platinum Underwriters Bermuda, Ltd.

                            By: /s/ Francois Bertrand
                                ---------------------
                                Name: Francois Bertrand
                                Title: Senior Vice President

                            Platinum Underwriters Reinsurance, Inc.

                            By: /s/ Edward F. Torres
                                ---------------------
                                Name: Edward F. Torres
                                Title: Senior Vice President

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                                                                   Exhibit 10.93

                      PLATINUM UNDERWRITERS HOLDINGS, LTD.

                                    Guaranty

         This Guaranty (the "Guaranty"), dated as of December 31, 2003, is made
and entered into by Platinum Underwriters Holdings, Ltd., a Bermuda company
("Guarantor"), and Platinum Underwriters Reinsurance, Inc., a Maryland insurance
company (the "Company").

                              W I T N E S S E T H:

         WHEREAS, the Company, a wholly-owned indirect subsidiary of Guarantor,
is engaged in the reinsurance business and intends to enter into reinsurance
contracts on or after the date hereof (each a "Reinsurance Contract") with
insurance companies, reinsurance companies and other reinsureds (each a
"Cedant");

         WHEREAS, subject to the terms and conditions set forth herein,
Guarantor desires to guarantee the Company's payment obligations to a Cedant
under a Reinsurance Contract to the extent that such payment obligations are not
disputed or contested by the Company (the "Undisputed Obligations");

         NOW THEREFORE, in consideration of the annual guaranty fee by the
Company to Guarantor and the mutual covenants and promises set forth herein,
Guarantor and the Company hereby agree as follows:

         1.       Guaranty. Subject to the provisions hereof, including without
limitation Section 3 hereof, Guarantor hereby absolutely, irrevocably and
unconditionally guarantees the payment when due of the Undisputed Obligations.
This Guaranty shall constitute a guarantee of payment and not of collection of
the Undisputed Obligations and shall remain in effect until the Undisputed
Obligations have been paid in full; provided, however, that in no case shall the
liability of Guarantor under this Guaranty exceed the amount of the Undisputed
Obligations.

         2.       Third Party Beneficiaries. Guarantor intends that each Cedant
that is a party to a Reinsurance Contract will be a third party beneficiary of
this Guaranty. In order to claim a benefit under the Guaranty, a Cedant must
first notify the Company in writing of the Company's failure to pay an
Undisputed Obligation and demand that payment be made by the Company (the
"Demand Notice"). If the Company shall fail to pay an Undisputed Obligation
within thirty (30) days after the date of receipt of Cedant's Demand Notice,
Cedant may make a demand for payment under this Guaranty upon Guarantor (a
"Payment Notice"). A Payment Notice shall be in writing and shall include a copy
of the Demand Notice, shall state that the Cedant is calling upon Guarantor to
pay an Undisputed Obligation under this Guaranty and shall specify in reasonable
detail the nature of the Undisputed Obligation, that the Company has failed to
pay the Undisputed Obligation and the date such payment was due. Guarantor shall
pay or otherwise satisfy Cedant's Payment Notice within thirty (30) business
days of Guarantor's receipt of the

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Payment Notice; provided, however, that Guarantor shall have no obligation to a
Cedant under this Guaranty unless it has received a Payment Notice satisfying
the foregoing requirements and such other information as the Guarantor may
reasonably request.

         3.       Setoffs and Counterclaims. Without limiting Guarantor's own
defenses and rights hereunder, Guarantor shall be entitled to all rights,
setoffs, counterclaims and other defenses to which the Company or any other
affiliate of Guarantor is or may be entitled, including without limitation,
those arising from or out of the Reinsurance Contracts. Notwithstanding the
foregoing, the liability of Guarantor under this Guaranty shall not be
diminished by: (i) any change in the time, manner or place of payment of any of
the Undisputed Obligations; or (ii) any insolvency, bankruptcy, reorganization,
or other similar proceeding by the Company.

         4.       Guaranty Fee. The Company will pay Guarantor a fee (the
"Guaranty Fee") in the amount of $2 million for the period from January 1, 2004
through December 31, 2004. The Guaranty Fee for each subsequent calendar year
shall be an amount equal to .66% of net premium estimated to be written by the
Company in such calendar year, as determined by the Company. The Guaranty Fee
shall be payable on or before the 31st day of March for the calendar year to
which the Guaranty Fee relates. To the extent that the actual amount of Net
Premiums Written, as reflected in the Company's Annual Statement, differs from
the estimated amount, the Guaranty Fee for that year shall be adjusted
retroactively to reflect such actual amount, and the amount of such adjustment,
together with interest thereon at the rate of 5%, shall be added to or
subtracted from the amount of the Guaranty Fee payable for the following
calendar year.

         5.       Guaranty Payments are Demand Loans. All payments made by the
Guarantor under this Agreement shall constitute loans from the Guarantor to the
Company. All such loans shall bear interest at 5% and shall be repayable by the
Company within three (3) business days after the Guarantor has made written
demand, together with all accrued but unpaid interest.

         6.       Tax Withholding. The Guaranty Fee and any interest paid on
Guaranty payments pursuant to Section 5 hereof shall be payable net of
withholding taxes that the Company determines are required to be withheld,
provided that if the Company withholds any such amounts, the Company shall pay
over the amount withheld to the appropriate tax authorities and provide the
Guarantor with a copy of the receipt for such payment. The Guarantor shall
indemnify the Company on an after-tax basis for any taxes, interest and
penalties assessed against the Company for failing to withhold unless the
Guarantor has notified the Company in writing to withhold and the Company fails
to do so, in which event the Guarantor shall indemnify the Company on an
after-tax basis for any taxes imposed upon the Company as a result of its
failure to withhold but not for any interest and penalties.

         7.       Successors and Assigns. This Agreement may not be assigned by
any party hereto without the prior written consent of the other party. This
Guaranty shall be binding upon Guarantor and the Company and their respective
successors and assigns and shall be for the benefit of any Cedant and its
successors and assigns.

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         8.       Subrogation. With respect to any Reinsurance Contract, the
Guarantor hereby unconditionally agrees that, until the payment and satisfaction
in full of all Undisputed Obligations under such Reinsurance Contract, it shall
not exercise any right or remedy arising by reason of any performance by it of
this Guaranty, whether by subrogation or otherwise, against the Company. Nothing
in this clause or in this Guaranty shall prevent Guarantor from exercising any
remedies or rights in order to safeguard or otherwise preserve or maintain any
such subrogation or other rights in whole or in part.

         9.       Amendment of Guaranty. No term or provision of this Guaranty
 shall be amended, modified, altered, waived or supplemented except in a writing
signed by Guarantor and the Company.

         10.      Termination. Guarantor may terminate this Guaranty at any time
 by providing written notice of such termination to the Company and upon the
effectiveness of such termination, Guarantor shall have no further liability
hereunder, except as provided in the last sentence of this paragraph. This
Guaranty also shall terminate immediately as of the day Guarantor no longer
controls the Company. For the purposes of this Section 8, the term "control"
means the ownership, either directly or indirectly, of 50% or more of the voting
stock of the Company. No such termination shall affect Guarantor's liability
with respect to any Reinsurance Contract entered into prior to the time the
termination is effective, which Reinsurance Contract shall remain guaranteed
pursuant to the terms of this Guaranty.

         11.      Notice. Any Payment Notice or other notice, request,
 instruction, correspondence or other document to be given hereunder to the
Guarantor shall be in writing as follows (unless a subsequent address has been
provided):

                  Platinum Underwriters Holdings, Ltd.
                  The Belvedere Building
                  69 Pitts Bay Road, 2nd Floor
                  Pembroke HM 08, Bermuda

                  Attn: Michael E. Lombardozzi
                        General Counsel
                        Fax No.: (441) 298-0752

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A copy of any Demand Notice sent or other notice, request, instruction,
correspondence or other document to be given hereunder to the Company shall be
in writing as follows (unless a subsequent address has been provided):

                  Platinum Underwriters Reinsurance, Inc.
                  2 World Financial Center
                  225 Liberty Street, Suite 2300
                  New York, NY  10281

                  Attn: James M. Conway
                        General Counsel
                        Fax No.: (212) 809-7565.

         12.      Miscellaneous. (a) This Guaranty shall in all respects be
governed by, and construed in accordance with, the laws of the State of New York
without giving effect to the conflicts of law principles thereof.

         (b)      This Guaranty embodies the entire agreement and understanding
between Guarantor and the Company concerning the subject matter hereof and
supersedes all prior agreements and understandings relating to the subject
matter hereof.

         (c)      The headings in this Guaranty are for purposes of reference
only, and shall not affect the meaning hereof.

         IN WITNESS WHEREOF, Guarantor and the Company have executed this
Guaranty as of the date first above written.

                                                PLATINUM UNDERWRITERS
                                                    HOLDINGS, LTD.

                                           By:    /s/ Gregory E.A. Morrison
                                                  -------------------------
                                           Name:  Gregory E.A. Morrison
                                           Title: President and Chief Executive
                                                  Officer

                                               PLATINUM UNDERWRITERS
                                                  REINSURANCE, INC.

                                           By:    /s/ Michael D. Price
                                                  ----------------------
                                           Name:  Michael D. Price
                                           Title: President

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