REPLIGEN CORP — Director's Dealing 2013

May 16, 2013

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: REPLIGEN CORP (RGEN)
CIK: 0000730272
Period of Report: 2013-05-14

Reporting Person: HERLIHY WALTER C (Director, PRESIDENT, CEO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2013-05-14	Common Stock	S	38486	$8.976	Disposed	549307	Direct
2013-05-14	Common Stock	G	10000	—	Disposed	539307	Direct
2013-05-15	Common Stock	S	1514	$8.85	Disposed	537793	Direct

Footnotes

F1: $8.9760 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $8.90 to $9.09, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.