AMENDMENT NO. 4 TO UNDERWRITING AGENCY AGREEMENT

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                                                                   Exhibit 10.18

                                 AMENDMENT NO. 4

                                       TO

                          UNDERWRITING AGENCY AGREEMENT
                        DATED DECEMBER 1, 2001, AS AMENDED

     This AMENDMENT NO. 4 TO UNDERWRITING AGENCY AGREEMENT (this "Amendment") is
made and entered into as of October 26, 2005, by and between Allied World
Assurance Company, Ltd (the "Company") and IPCRe Underwriting Services Limited
(the "Underwriting Agent").

                                   WITNESSETH:

     WHEREAS, the Company and the Underwriting Agent have entered into an
Underwriting Agency Agreement, dated as of December 1, 2001, as amended from
time to time (the "Agreement"); and

     WHEREAS, the Company and the Underwriting Agent desire to further amend the
Agreement in accordance with the terms and conditions contained herein;

     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the Company and the Underwriting
Agent agree as follows:

     1. It is hereby agreed that Section 2.2 A of the Agreement be deleted in
its entirety and the following be inserted in lieu thereof:

          "Except as otherwise specifically provided, the annual original
          premium written for the Subject Business ceded to the Company pursuant
          to reinsurance treaties entered into by the Underwriting Agent on
          behalf of the Company shall not be limited in the aggregate;"

     2. It is hereby agreed that Section 2.2 C of the Agreement be deleted in
its entirety and the following be inserted in lieu thereof:

          "The maximum limit of liability under reinsurance treaties entered
           into by the Underwriting Agent on behalf of the Compan