SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES 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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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. Date of Event Requiring Statement (Month/Day/Year) 05/17/2006	3. Issuer Name and Ticker or Trading Symbol Darwin Professional Underwriters Inc [ DR ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director X 10% Owner Officer (give title below) Other (specify below)	5. 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 Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Series A Preferred Stock	114,860	I	See Footnote(1)
Series C Preferred Stock	2,465	I	See Footnote(1)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series B Convertible Preferred Stock	(2)	(2)	Common Stock	900,000	$219.0867	I	See Footnote(1)

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. 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 90% of the issued and outstanding voting securities of Darwin Professional Underwriters, Inc. ("DR") 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.

2. The shares of Series B Convertible Preferred Stock are convertible at any time, at the option of the holder, into shares of Common Stock. The shares of Series B Convertible Preferred Stock do not have an expiration date.

	/s/ Weston M. Hicks	05/17/2006
	/s/ Weston M. Hicks	05/17/2006
	** 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 5 (b)(v).
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