REPLIGEN CORP - Director's Dealing 2012

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: REPLIGEN CORP (RGEN)
CIK: 0000730272
Period of Report: 2012-08-31

Reporting Person: Kelly William J (CFO)

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2012-08-31	Common Stock	M	80000	$4.82	Acquired	85000	Direct
2012-08-31	Common Stock	M	10000	$3.33	Acquired	95000	Direct
2012-08-31	Common Stock	S	40409	$5.50	Disposed	54591	Direct
2012-08-31	Common Stock	S	8500	$5.51	Disposed	46091	Direct
2012-08-31	Common Stock	S	10700	$5.52	Disposed	35391	Direct
2012-08-31	Common Stock	S	9681	$5.53	Disposed	25710	Direct
2012-08-31	Common Stock	S	8000	$5.54	Disposed	17710	Direct
2012-08-31	Common Stock	S	9900	$5.55	Disposed	7810	Direct
2012-08-31	Common Stock	S	4803	$5.56	Disposed	3007	Direct
2012-08-31	Common Stock	S	800	$5.57	Disposed	2207	Direct
2012-08-31	Common Stock	S	1500	$5.59	Disposed	707	Direct
2012-08-31	Common Stock	S	400	$5.60	Disposed	307	Direct
2012-08-31	Common Stock	S	100	$5.61	Disposed	207	Direct
2012-08-31	Common Stock	S	107	$5.62	Disposed	100	Direct
2012-08-31	Common Stock	S	100	$5.63	Disposed	0	Direct

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2012-08-31	Stock Option (Right to Buy)	$4.82	M	80000	Disposed	2018-03-31	Common Stock (80000)	Direct
2012-08-31	Stock Option (Right to Buy)	$3.33	M	10000	Disposed	2020-07-15	Common Stock (10000)	Direct

F1: 20,000 shares vested and became exercisable at each of the following dates: 3/31/2009, 3/31/2010, 3/31/2011 and 3/31/2012.

F2: 5,000 shares each vested and became exercisable at 7/15/2011 and 7/15/2012.