SEC FORM 4

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

HARTZBAND MERYL D

(Last)

(First)

(Middle)

C/O ALTERRA CAPITAL HOLDINGS LIMITED

ALTERRA HOUSE, 2 FRONT STREET

(Street)

HAMILTON, BERMUDA

HM 11

(City)

(State)

(Zip)

2. Issuer Name and Ticker or Trading Symbol
ALTERRA CAPITAL HOLDINGS Ltd [ ALTE ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	10% Owner
	Officer (give title below)	Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
05/01/2013

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Shares	05/01/2013		D		8,465,675	D	⁽²⁾	0	I	By Trident III Professionals Fund, L.P. and Trident III, L.P.⁽¹⁾
Common Shares	05/01/2013		D		14,000	D	⁽³⁾	0	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Warrants (right to buy)	$18.585	05/01/2013		M			5,122,707.11	⁽⁴⁾	12/15/2015	Common Shares	5,122,707.11	⁽⁵⁾	0	I	By Trident III Professionals Fund, L.P. and Trident III, L.P.⁽¹⁾

Explanation of Responses:

1. Filing is made in respect of warrants to purchase common shares of Alterra Capital Holdings Limited (the "Issuer") held by Trident III Professionals Fund, L.P. and Trident III, L.P. Ms. Hartzband is a member and senior principal of Stone Point Capital LLC, a shareholder and a director of Stone Point GP Ltd., which is the general partner of Trident III Professionals Fund, L.P., and a member of the investment committee and owner of one of the five general partners of Trident Capital III, L.P., which is the general partner of Trident III, L.P. Ms. Hartzband disclaims beneficial ownership of the common shares of the Issuer held of record or beneficially by Trident III Professionals Fund, L.P. and Trident III, L.P., except as to the extent of any pecuniary interest therein.

2. Disposed of pursuant to the Agreement and Plan of Merger, dated as of December 18, 2012 (the "Merger Agreement") between the Issuer, Markel Corporation ("Markel") and Commonwealth Merger Subsidiary Limited in exchange on a per share basis for (i) the amount of shares of Markel common stock equal to the number of shares of Issuer common stock multiplied by 0.04315 plus (ii) $10.00 in cash, without interest, together with any cash paid in lieu of fractional shares relating to each award and form of ownership (the "Merger Consideration").

3. Disposed of pursuant to the Merger Agreement in exchange on a per share basis for the Merger Consideration. All of the shares of common stock of the Issuer exchanged represented restricted stock that automatically vested upon the closing of the transactions contemplated by the Merger Agreement.

4. All warrants are immediately exercisable.

5. Disposed of pusuant to the Merger Agreement and the terms of the warrants in exchange for warrants exercisable for the Merger Consideration.

Remarks:

	H. Matthew Crusey, Attorney-in-Fact	05/03/2013
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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