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: 2013-05-09

Reporting Person: GRIFFITH MICHAEL A (Director)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2013-05-09	Common Stock	A	5342	—	Acquired	7342	Direct

Footnotes

F1: Mr. Griffith was awarded 5,342 Restricted Stock Units. Each Restricted Stock Unit represents a contingent right to receive one share of Repligen Corporation's Common Stock. The Restricted Stock Units vest on May 9, 2014. The Restricted Stock Units may be settled only by delivering shares of Repligen Corporation's Common Stock, and thus, the grant is being reported in Table 1 as allowed per SEC guidance.