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	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	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* ALLEGHANY CORP /DE (Last) (First) (Middle) 7 TIMES SQUARE TOWER 17TH FLOOR (Street) NEW YORK NY 10036 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Darwin Professional Underwriters Inc [ DR ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 05/24/2006
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X 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)
			Code	V	Amount	(A) or (D)	Price
Common Stock	05/24/2006		C		9,371,096(1)	A	(2)	9,371,096	I	See Note 3(3)
Series A Preferred Stock	05/24/2006		J(4)		114,860	D	$20(5)	0	I	See Note 3(3)
Series C Preferred Stock	05/24/2006		J(4)		2,465	D	$1,000(6)	0	I	See Note 3(3)

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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series B Convertible Preferred Stock	$13.28(1)	05/24/2006		J(7)			72,749	(8)	(8)	Common Stock	5,478,904(1)	$1,120.65(7)	124,429	I	See Note 3(3)
Series B Convertible Preferred Stock(1)	(2)	05/24/2006		C			124,429	(2)	(2)	Common Stock	9,371,096(1)	$0	0	I	See Note 3(3)

1. Name and Address of Reporting Person* ALLEGHANY CORP /DE (Last) (First) (Middle) 7 TIMES SQUARE TOWER 17TH FLOOR (Street) NEW YORK NY 10036 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* ALLEGHANY INSURANCE HOLDINGS LLC (Last) (First) (Middle) 7 TIMES SQUARE TOWER 17TH FLOOR (Street) NEW YORK NY 10036 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. Gives effect to the 33-for-2 common stock split, which became effective on May 24, 2006.

2. In accordance with the terms of the Series B Convertible Preferred Stock, in connection with the closing of the initial public offering (the "IPO") of Darwin Professional Underwriters, Inc. ("DR") on May 24, 2006, 124,429 shares of Series B Convertible Preferred Stock converted into 9,371,096 shares of DR Common Stock. The shares of Series B Convertible Preferred Stock had no expiration date.

3. The reported securities are owned directly by Alleghany Insurance Holdings LLC ("AIHL") and are beneficially owned indirectly by Alleghany Corporation ("Alleghany"), which is the sole stockholder of AIHL. This report if filed jointly by Alleghany and by AIHL, 7 Times Square Tower, New York, New York 10036. Because AIHL owns, and Alleghany beneficially owns, more than 50% of the issued and outstanding shares of DR common stock and AIHL has elected three Alleghany officers to serve as its representatives on the Board of Directors of DR, each of AIHL and Alleghany may be deemed to be a director by deputization of DR.

4. The reported securities were redeemed by the issuer at a redemption price per share equal to the liquidation value.

5. Amount equal to liquidation preference of one share of Series A Preferred Stock.

6. Amount equal to liquidation preference of one share of Series C Preferred Stock.

7. In accordance with the terms of the Series B Convertible Preferred Stock, in connection with the closing of the IPO of DR on May 24, 2006, 72,749 shares of Series B Convertible Preferred Stock were redeemed at a redemption price per share equal to the product of (1) the number of shares of common stock in to which one share of Series B Convertible Preferred Stock would be convertible and (2) an amount equal to (x) the IPO price less (y) the underwriting discount.

8. The shares of Series B Convertible Preferred Stock had no expiration date.

	Aileen C. Meehan (attorney-in-fact)	05/26/2006
	Aileen C. Meehan (attorney-in-fact)	05/26/2006
	** Signature of Reporting Person	Date
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