REPLIGEN CORP — Director's Dealing 2016

May 13, 2016

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: REPLIGEN CORP (RGEN)
CIK: 0000730272
Period of Report: 2016-05-11

Reporting Person: DAWES KAREN A (Director)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2016-05-11	Common Stock	A	2505	—	Acquired	42746	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2016-05-11	Stock Option (Right to Buy)	$26.12	A	4783	Acquired	2026-05-11	Common Stock (4783)	Direct

Footnotes

F1: Ms. Dawes was awarded 2,505 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 11, 2017. 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.

F2: Award vests in full one year from grant date on May 11, 2017.