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
X	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* ARDSLEY ADVISORY PARTNERS (Last) (First) (Middle) 262 HARBOR DRIVE, 4TH FLOOR (Street) STAMFORD CT 06902 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol OM GROUP INC [ OMG ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 08/26/2003
	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)
			Code	V	Amount	(A) or (D)	Price
Common Stock	08/26/2003		S		157,500	D	$13.1672	2,816,700	I(1)(2)(3)	(1)(2)(3)(1)(2)(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

Explanation of Responses:

1. The shares of Common Stock are held directly by Ardsley Offshore Fund Ltd., a British Virgin Islands corporation ("Ardsley Offshore"), as to 750,000 shares; Ardsley Partners Fund II, L.P., a Delaware limited partnership ("Ardsley Fund II"), as to 635,000 shares; Ardsley Partners Institutional Fund, L.P., a Delaware limited partnership, ("Ardsley Institutional"), as to 320,000 shares; Advantage Advisers Augusta Fund, L.L.C., a Delaware limited liability company ("Augusta"), as to 275,000 shares; Philip J. Hempleman, managing partner of Ardsley Advisory Partners and general partner of Ardsley Partners I as to 540,000 shares; the Carter Hempleman Trust ("Carter Trust"), as to 92,000 shares; the Spencer Hempleman Trust ("Spencer Trust"), as to 92,200 shares; the Hempleman Family Trust ("Family Trust"), as to 100,000 shares; and Marion Lynton ("Lynton") as to 12,500 shares.

2. Ardsley Advisory Partners serves as investment manager to, and has investment discretion over the securities held by Ardsley Offshore and the Lynton account. Ardsley Advisory Partners also serves as a non-managing member of Augusta Management L.L.C., the investment adviser of Augusta and has investment discretion over the securities held by Augusta. Ardsley Partners I serves as the general partner of, and has investment discretion over the securities held by Ardsley Fund II and Ardsley Institutional. Ardsley Partners I also serves as the general partner of Ardsley Advisory Partners and Philip Hempleman serves as the Managing Partner of each of Ardsley Partners I and Ardsley Advisory Partners. Philip Hempleman also serves as trustee to and has discretion over the securities held by the Carter Trust, the Spencer Trust and the Family Trust.

3. Ardsley Advisory Partners and Ardsley Partners I each disclaim any beneficial ownership of any of the Issuer's securities to which this Form 4 relates for the purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except as to such securities representing in which each such person may be deemed to have an indirect pecuniary interest pursuant to Rule 16a-1(a)(2).

	/s/ Steven Napoli	08/28/2003
	** 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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