ZNT Zenith National Insurance Corp.

CUSIP No. 989390109 13G/A Page 2 of 7 Pages

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 (1) NAMES OF REPORTING PERSONS
 I.R.S. IDENTIFICATION NO.
 OF ABOVE PERSONS (ENTITIES ONLY)
 Centaurus Capital LP
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 (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP **
 (a) [X]
 (b) [ ]
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 (3) SEC USE ONLY
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 (4) CITIZENSHIP OR PLACE OF ORGANIZATION
 United Kingdom
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NUMBER OF (5) SOLE VOTING POWER
 -0-
SHARES ______________________________________________________________

BENEFICIALLY (6) SHARED VOTING POWER
 1,496,273
OWNED BY ______________________________________________________________

EACH (7) SOLE DISPOSITIVE POWER
 -0-
REPORTING ______________________________________________________________

PERSON WITH (8) SHARED DISPOSITIVE POWER
 1,496,273
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 (9) AGGREGATE AMOUNT BENEFICIALLY OWNED
 BY EACH REPORTING PERSON
 1,496,273
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 (10) CHECK BOX IF THE AGGREGATE AMOUNT
 IN ROW (9) EXCLUDES CERTAIN SHARES ** [ ]
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 (11) PERCENT OF CLASS REPRESENTED
 BY AMOUNT IN ROW (9)
 3.9%
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 (12) TYPE OF REPORTING PERSON **
 PN
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 ** SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 989390109 13G/A Page 3 of 7 Pages

----------------------------------------------------------------------------
 (1) NAMES OF REPORTING PERSONS
 I.R.S. IDENTIFICATION NO.
 OF ABOVE PERSONS (ENTITIES ONLY)
 Centaurus Capital Limited
-----------------------------------------------------------------------------
 (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP **
 (a) [X]
 (b) [ ]
-----------------------------------------------------------------------------
 (3) SEC USE ONLY
-----------------------------------------------------------------------------
 (4) CITIZENSHIP OR PLACE OF ORGANIZATION
 United Kingdom
-----------------------------------------------------------------------------
NUMBER OF (5) SOLE VOTING POWER
 -0-
SHARES ______________________________________________________________

BENEFICIALLY (6) SHARED VOTING POWER
 1,496,273
OWNED BY ______________________________________________________________

EACH (7) SOLE DISPOSITIVE POWER
 -0-
REPORTING ______________________________________________________________

PERSON WITH (8) SHARED DISPOSITIVE POWER
 1,496,273
-----------------------------------------------------------------------------
 (9) AGGREGATE AMOUNT BENEFICIALLY OWNED
 BY EACH REPORTING PERSON
 1,496,273
-----------------------------------------------------------------------------
 (10) CHECK BOX IF THE AGGREGATE AMOUNT
 IN ROW (9) EXCLUDES CERTAIN SHARES ** [ ]
-----------------------------------------------------------------------------
 (11) PERCENT OF CLASS REPRESENTED
 BY AMOUNT IN ROW (9)
 3.9%
-----------------------------------------------------------------------------
 (12) TYPE OF REPORTING PERSON **
 OO
-----------------------------------------------------------------------------
 ** SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 989390109 13G/A Page 4 of 7 Pages

Item 1(a). Name of Issuer:

 The name of the issuer is ZENITH NATIONAL INSURANCE CORP. (the
"Company").

Item 1(b). Address of Issuer's Principal Executive Offices:

 The Company's principal executive offices are located at 21255 Califa
Street, Woodland Hills, California 91367-5021.

Item 2(a). Name of Person Filing:

 This statement is filed by:
 (i) Centaurus Capital LP, a United Kingdom limited partnership
 ("Centaurus"), which serves as investment manager to Centaurus
 International Risk Arbitrage Master Fund Limited ("CIRAF") and
 certain managed accounts, with respect to the shares of Common
 Stock directly owned by CIRAF and the managed accounts; and

 (ii) Centaurus Capital Limited, a corporation organized under
 the laws of the United Kingdom ("CCL"), which serves as
 the general partner to Centaurus, with respect to the
 shares of Common Stock directly owned by CIRAF and the
 managed accounts.

 The foregoing persons are hereinafter sometimes collectively referred
to as the "Reporting Persons." Any disclosures herein with respect to persons
other than the Reporting Persons are made on information and belief after making
inquiry to the appropriate party.

Item 2(b). Address of Principal Business Office or, if None, Residence:

 The address of the business office of each of the Reporting Persons is
33 Cavendish Square, 16th Floor, London, W1G OPW, United Kingdom.

Item 2(c). Citizenship:

 Centaurus is a limited partnership organized under the laws of the
United Kingdom. CCL is a corporation organized under the laws of the United
Kingdom.


Item 2(d). Title of Class of Securities:

 Common Stock (the "Common Stock").

CUSIP No. 989390109 13G/A Page 5 of 7 Pages

Item 2(e). CUSIP Number:

 989390109

Item 3. If this statement is filed pursuant to Rules 13d-1(b) or 13d-2(b) or
(c), check whether the person filing is a:

 (a) [ ] Broker or dealer registered under Section 15 of the Act,

 (b) [ ] Bank as defined in Section 3(a)(6) of the Act,

 (c) [ ] Insurance Company as defined in Section 3(a)(19) of the
 Act,

 (d) [ ] Investment Company registered under Section 8 of the
 Investment Company Act of 1940,

 (e) [ ] Investment Adviser registered under Section 203 of the
 Investment Advisers Act of 1940,

 (f) [ ] Employee Benefit Plan or Endowment Fund in accordance
 with 13d-1 (b)(1)(ii)(F),

 (g) [ ] Parent Holding Company or control person in accordance
 with Rule 13d-1 (b)(ii)(G),

 (h) [ ] Savings Associations as defined in Section 3(b) of the
 Federal Deposit Insurance Act,

 (i) [ ] Church Plan that is excluded from the definition of an
 investment company under Section 3(c)(14) of the Investment
 Company Act of 1940,

 (j) [ ] Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

 If this statement is filed pursuant to 13d-1(c), check this box: [x]


Item 4. Ownership.

 A. Centaurus Capital LP
 (a) Amount beneficially owned: 1,496,273
 (b) Percent of class: 3.9%. The percentages used herein and in
 the rest of this Schedule 13G/A are calculated based upon the
 37,930,463 shares of Common Stock issued and outstanding as of
 April 15, 2010 as reported in the Form 10-Q for the quarterly
 period ending March 31, 2010 as filed by the Company on April
 21, 2010.
 (c)(i) Sole power to vote or direct the vote: -0-
 (ii) Shared power to vote or direct the vote: 1,496,273
 (iii) Sole power to dispose or direct the disposition: -0-
 (iv) Shared power to dispose or direct the disposition: 1,496,273

CUSIP No. 989390109 13G/A Page 6 of 7 Pages


 B. Centaurus Capital Limited
 (a) Amount beneficially owned: 1,496,273
 (b) Percent of class: 3.9%
 (c)(i) Sole power to vote or direct the vote: -0-
 (ii) Shared power to vote or direct the vote: 1,496,273
 (iii) Sole power to dispose or direct the disposition: -0-
 (iv) Shared power to dispose or direct the disposition: 1,496,273


Item 5. Ownership of Five Percent or Less of a Class.

 If this statement is being filed to report the fact as of the date hereof
the reporting person has ceased to be the beneficial owner of more than five
percent of the class of securities, check the following [x].


Item 6. Ownership of More than Five Percent on Behalf of Another Person.

 Not applicable.


Item 7. Identification and Classification of the Subsidiary Which Acquired
the Security Being Reported on by the Parent Holding Company.

 Not applicable.


Item 8. Identification and Classification of Members of the Group.

 Not applicable.


Item 9. Notice of Dissolution of Group.

 Not applicable.


Item 10. Certification.

 Each of the Reporting Persons hereby makes the following certification:

 By signing below each Reporting Person certifies that, to the best of
its knowledge and belief, the securities referred to above were not acquired and
are not held for the purpose of or with the effect of changing or influencing
the control of the issuer of the securities and were not acquired and are not
held in connection with or as a participant in any transaction having that
purpose or effect.

CUSIP No. 989390109 13G/A Page 7 of 7 Pages


 SIGNATURES

After reasonable inquiry and to the best of our knowledge and belief, the
undersigned certify that the information set forth in this statement is true,
complete and correct.


DATED: May 18, 2010

 Centaurus Capital LP

 By: Centaurus Capital Limited,
 its General Partner

 /s/ Paul Leary
 -----------------------------
 Name: Paul Leary
 Title: Director


 Centaurus Capital Limited

 /s/ Paul Leary
 -----------------------------
 Name: Paul Leary
 Title: Director