Exhibit  10.16


WINTERTHUR GROUP                  Head Office         General Guisan-Strasse 40
                                                      CH-8401 Winterthur
                                                      Telephone +41 52 261 61 10
                                                      www.winterthur.com


REGISTERED
Mr. Brian O'Hara
Chief Executive Officer
XL Insurance (Bermuda) Ltd
One Bermudiana Road
Hamilton HM11
Bermuda


John R. Dacey
CFO
john.dacey@winterthur.ch
July 27, 2004


VARIATION TO THE SPA
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WITHOUT PREJUDICE


Dear Brian,

We would like to thank you for the constructive meeting of last Thursday, 23
July 2004. We set out below certain amendments to the Second Amended and
Restated Agreement dated 15 February 2001 for the sale and purchase of
Winterthur International and between Winterthur Swiss Insurance Company
("Winterthur") and XL Insurance (Bermuda) Ltd ("XL") (the "SPA") discussed
between the parties on the occasion of the said meeting.

We refer to Clause 18.8 SPA, and write to record our and your agreement to the
following variations to the SPA and the procedure there recorded for the purpose
of permitting each of XL and Winterthur additional time for the preparation and
determination of the Seasoned Net Reserves Statement:

         1.       XL agrees to serve a preliminary draft Seasoned Net Reserves
                  Statement on Winterthur by 31 August 2004. Such preliminary
                  draft shall be provided without prejudice and shall contain or
                  be accompanied by materially the same information or
                  documentation (especially in electronic form) as is available
                  and of a type that will be required to be included in or
                  accompany the Seasoned Net Reserves Statement to be delivered
                  pursuant to Clause 4.2.2 of the SPA.

         2.       In the period within 90 Business Days following receipt of the
                  preliminary draft Seasoned Net Reserves Statement referred to
                  above, senior executives from our respective organisations
                  shall meet on a without prejudice basis to discuss the
                  preliminary draft Seasoned Net Reserves Statement and whether
                  any disputes over the content thereof should be resolved other
                  than through the procedure specified in the SPA.



Variation to the SPA
Page 2
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         3.       If XL and Winterthur do not reach agreement in relation to the
                  matters referred to in paragraph 2 above within such 90
                  Business Day period, XL shall deliver the Seasoned Net
                  Reserves Statement referred to in Clause 4.2.2 SPA. Unless
                  Winterthur serves written notice on XL requiring the delivery
                  of the Seasoned Net Reserves Statement, any such Statement can
                  only be delivered by XL to Winterthur within 30 Business Days
                  of the expiry of the period of 90 Business Days referred to in
                  paragraph 2 above. However, in the event that Winterthur
                  serves written notice on XL requiring the delivery of the
                  Seasoned Net Reserves Statement (which notice can be served by
                  Winterthur at any time after the service of the preliminary
                  draft statement under paragraph 1 above), the Seasoned Net
                  Reserves Statement must be delivered by XL within 30 Business
                  Days following the receipt by XL of the said written
                  notification from Winterthur. The period of time of 30
                  Business Days following the End Date referred to in Clause
                  4.2.2 of the SPA for delivery of the Seasoned Net Reserves
                  Statement by XL is extended accordingly. Once delivery of the
                  Seasoned Net Reserves Statement has occurred in accordance
                  with the provisions set out above, the parties shall proceed
                  in accordance with Clause 4.2.4 and subsequent clauses of the
                  SPA.

         4.       Solely for the purposes of the provisions of Clause 4.2.3 of
                  the SPA and the obligations thereby imposed on XL and the
                  rights thereby conferred on Winterthur (to include its
                  Accountants and Actuaries) the preliminary draft Statement to
                  be served under paragraph 1 above will be treated as if it
                  were the Seasoned Net Reserves Statement delivered under
                  Clause 4.2.2 of the SPA.

         5.       XL and Winterthur confirm that any amendment to the SPA as
                  effected by this letter shall not affect in any way the
                  calculation of the Seasoned Net Reserves Amount under Clause
                  4.2 of the SPA except as set forthwith in paragraph 3 above.
                  For the avoidance of doubt this letter shall 1) not in any way
                  affect the economic, financial or other nature of reserve
                  seasoning, including, without limitation, the fact that losses
                  occurring subsequent to June 30, 2004 are not included in the
                  Seasoned Net Reserves Amount and 2) not affect in any way the
                  determination of the date and/or rate to be used for foreign
                  exchange conversion of any amount in connection therewith.

         6.       The provisions of this letter, including the extension of time
                  referenced in paragraph 3 above, shall apply with equal force
                  and effect in relation to the provisions of SPA relating to
                  the Seasoned Net Premiums Receivable Statement.

         7.       Save as aforesaid the terms of the SPA shall remain un-amended
                  and in full force and effect.



Variation to the SPA
Page 3
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Kindly confirm your agreement to such variations by returning to us a copy of
this letter endorsed with your signature. Each party hereto has asserted various
legal rights against the other. Nothing herein shall operate as any waiver of
either party's rights in relation to any alleged breach of contract by the
other.


Yours sincerely,

/s/ John R. Dacey                            /s/ Martha Boeckenfeld

John R. Dacey                                Martha Boeckenfeld


Agreed by XL Insurance (Bermuda) Ltd


/s/ Brian M. O'Hara
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cc:   Paul Giordano
      Clive Tobin
      Jerry de St. Paer