REPLIGEN CORP — Major Shareholding Notification 2011

Jul 13, 2011

SC 13D/A 1 schedule13da4.htm schedule13da4.htm Licensed to: Cenveo Document Created using EDGARizerAgent 5.3.0.0 Copyright 1995 - 2009 Thomson Reuters. All rights reserved.

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Schedule 13D

Under the Securities Exchange Act of 1934

(Amendment No. 4)*

REPLIGEN CORP

(Name of Issuer)

Common Stock, Par Value $0.01 Per Share

(Title of Class of Securities)

759916 10 9

(CUSIP Number)

Barry L. Fischer

Thompson Coburn Fagel Haber

55 East Monroe Street

Suite 3700

Chicago, IL 60603

(312) 346-7500

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

July 12, 2011

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of Rule 13d-1(e), (f) or (g), check the following box EFPlaceholder o .

Note: Schedules filed in paper format shall include a signed original and five copies of the Schedule, including all exhibits. See Rule 13d-7(b) for other parties to whom copies are being sent.

*The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 590418109

1	NAMES OF REPORTING PERSON Individual Retirement Accounts for the benefit of Ronald L. Chez and Ronald L. Chez Individually
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)	(a) o (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions) PF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION United States of America

NUMBER OF SHARES		SOLE VOTING POWER 2,601,538
BENEFICIALLY OWNED BY EACH	8	SHARED VOTING POWER 0
REPORTING PERSON WITH	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 2,601,538
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,601,538

12	CHECK IF THE AGGREGA TE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 8.4% (1)
14	TYPE OF REPORTING PERSON (See Instructions) IN

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(1) Based upon 30,812,257 shares of the Issuer’s common stock issued and outstanding as of May 20, 2011, as reported on the Issuer’s Form 10-K for the fiscal year ended March 31, 2011.

2

Pursuant to Rule 13d-2 of Regulation 13D-G of the General Rules and Regulations under the Securities Exchange Act of 1934, as amended, the undersigned, Ronald L. Chez (the "Reporting Person") hereby amends his statement on Schedule 13D dated January 30, 2007, as amended by Amendment No. 1 to Schedule 13D dated July 13, 2007; Amendment No. 2 to Schedule 13D dated October 20, 2008; and Amendment No. 3 to Schedule 13D dated June 20, 2011 (collectively, the “Schedule 13D”). This Statement constitutes Amendment No. 4 to the Schedule 13D. Unless otherwise indicated herein, there are no material changes to the information set forth in the Schedule 13D.

Item 5. Interest in Securities of the Issuer is hereby amended and restated in its entirety as follows :

(a) The aggregate number of shares of the Stock owned beneficially by the Reporting Person is 2,601,538 (the "Shares") constituting approximately 8.4% of the outstanding shares of the Stock. The percentages in this Item 5(a) are based upon 30,812,257 shares of the Issuer’s common stock issued and outstanding as of May 20, 2011, as reported on the Issuer’s Form 10-K for the fiscal year ended March 31, 2011.

(b) The Reporting Person has the sole power (and no shared power) to vote or dispose of or direct the disposition of Shares owned by such Reporting Person.

(c) Since June 17, 2011 (the date of the event that necessitated the filing of the immediately prior amendment to the Schedule 13D), the Reporting Person purchased shares of Stock (through open market transactions) as follows:

DATE	QUANTITY	PRICE PER SHARE
6/17/2011	9,800	$3.55
6/20/2011	4,300	$3.52
6/21/2011	2,000	$3.48
6/22/2011	13,100	$3.44
6/28/2011	1,000	$3.59
6/30/2011	4,650	$3.65
7/5/2011	3,000	$3.53
7/5/2011	1,000	$3.61
7/7/2011	2,000	$3.48
7/8/2011	4,500	$3.50
7/11/2011	38,501	$3.55
7/12/2011	34,100	$3.56

(d) Not applicable.

(e) Not applicable.

3

SIGNATURE

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

Dated as of July 13, 2011

/s / Barry L. Fischer Barry L. Fischer, attorney-in-fact for Ronald L. Chez

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