REPLIGEN CORP — Director's Dealing 2021

May 18, 2021

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: REPLIGEN CORP (RGEN)
CIK: 0000730272
Period of Report: 2021-05-13

Reporting Person: MUIR GLENN P (Director)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2021-05-13	Common Stock	A	457	$0.00	Acquired	6362	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2021-05-13	Stock Option (Right to Buy)	$169.65	A	1151	Acquired	2031-05-13	Common Stock (1151)	Direct

Footnotes

F1: Mr. Muir was awarded 457 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 the earlier of May 13, 2022, one year from the grant date, or the date of the next annual meeting of the Company's shareholders, which has not yet been determined. 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 on the earlier of May 13, 2022, one year from grant date, or on the date of the next annual meeting of the Company's shareholders, which has not yet been determined.