Exhibit 10.54

FOURTH AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT

THIS FOURTH AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT (this"Amendment") is entered into as of
December 27, 2005, between ZENITH NATIONAL INSURANCE CORP., a Delaware corporation (the"Company"), and BANK OF AMERICA, N.A., a national banking
association (the"Bank").

RECITALS

A.    The
Company and the Bank are party to that certain Amended and Restated Credit Agreement dated as of September 30, 2002 (as heretofore modified, amended or
supplemented, the "Credit Agreement"). Unless otherwise defined herein, defined terms used herein shall have the meanings given such terms in the Credit
Agreement.

B.    The
Company and the Bank have agreed to amend the Credit Agreement in certain respects.

NOW THEREFORE,in consideration of the foregoing and for other good and valuable consideration, the receipt and adequacy of which are
hereby acknowledged, the Company and the Bank agree as follows:

1.Amendments.Subject to satisfaction of the conditions precedent set forth in Section 2hereof, the Credit
Agreement is hereby amended as follows:



2.Conditions Precedent to Amendments.The amendments in Section 1hereof shall be effective as of the date
hereof when the Bank receives:



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3.Representations and Warranties.The Company represents and warrants to the Bank as follows:



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6.Effect of Amendment.This Amendment is a Loan Document. The amendment effected hereunder is expressly limited
to the matters contained herein. Except as amended hereby, the Credit Agreement and the other Loan Documents are unchanged and are hereby ratified and confirmed.

7.Counterparts.This Amendment may be executed in any number of counterparts and by the parties hereto in
separate counterparts, each of which when so executed and delivered shall be deemed to be an original and all of which taken together shall constitute one and the same instrument.

8.Governing Law.This Amendment shall be governed by and construed in accordance with the laws of the State of
California, without regard to conflict of laws principles.

9.ENTIRETY.THIS AMENDMENT, THE CREDIT AGREEMENT AS AMENDED
HEREBY, AND THE OTHER LOAN DOCUMENTS EMBODY THE ENTIRE AGREEMENT BETWEEN THE PARTIES AND SUPERCEDE ALL PRIOR AGREEMENTS AND UNDERSTANDINGS, IF ANY, RELATING TO THE SUBJECT MATTER HEREOF. THESE LOAN
DOCUMENTS REPRESENT THE FINAL AGREEMENT BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.

10.Parties.This Amendment binds and inures to the benefit of the Company, the Bank, and their respective
successors and permitted assigns.

[Remainder
of Page Intentionally Left Blank.
Signature Page Follows.]

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|ZENITH NATIONAL INSURANCE CORP., as the Company |                                                                           
|----------------------------------------------- | --------------------------------------------------------------------------
|By:                                             | /s/STANLEY R. ZAXName:  Stanley R. Zax
Title:    President and Chairman   
|BANK OF AMERICA, N.A., as the Bank              |                                                                           
|By:                                             | /s/MICHAEL W. COLONName:  Michael W. Colon
Title:    Senior Vice President

Signature Page to Fourth Amendment to Credit Agreement

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