REPLIGEN CORP — Director's Dealing 2012

Mar 26, 2012

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: REPLIGEN CORP (RGEN)
CIK: 0000730272
Period of Report: 2012-03-22

Reporting Person: WITT DANIEL P (Vice President)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2012-03-22	Common Stock	M	10000	$3.24	Acquired	52200	Direct
2012-03-22	Common Stock	F	6493	$4.99	Disposed	45707	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2012-03-22	Stock Option (Right to Buy)	$3.24	M	10000	Disposed	2012-04-11	Common Stock (10000)	Direct

Footnotes

F1: Payment made via forfeiture of 6,493 shares of Common Stock valued at the Closing Price of $4.99 on March 22, 2012.