Repligen Corporation (RGEN) director boosts holdings via 3,366-share option exercise

Rhea-AI Filing Summary

Repligen Corporation reported that one of its directors exercised a stock option for common shares. On 12/16/2025, the director acquired 3,366 shares of common stock through an option exercise at a price of $26.12 per share, increasing the director’s direct beneficial ownership to 36,622 common shares after the transaction. The related stock option, which is fully vested and exercisable, covers 3,366 shares of common stock and carries an exercise price of $26.12 with an expiration date of May 11, 2026.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

MUIR GLENN P

(Last) (First) (Middle)

C/O REPLIGEN CORPORATION

41 SEYON ST., BLDG 1, STE 100

(Street)

WALTHAM MA 02453

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
REPLIGEN CORP [ RGEN ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
12/16/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	12/16/2025		M		3,366	A	$26.12	36,622	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (Right to Buy)	$26.12	12/16/2025		M		3,366		(1)	05/11/2026	Common Stock	3,366	$0.00	3,366	D

Explanation of Responses:

1. This option is fully vested and exercisable.

	/s/ Jennifer Carmichael (Attorney in Fact)	12/17/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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FAQ

What insider transaction was reported for Repligen Corp (RGEN)?

A director of Repligen Corp reported exercising a stock option, acquiring 3,366 shares of common stock on 12/16/2025.

At what price were the Repligen Corp (RGEN) shares acquired in this Form 4?

The shares were acquired at an exercise price of $26.12 per share through a stock option exercise.

How many Repligen Corp (RGEN) shares does the reporting person own after the transaction?

Following the reported transaction, the director beneficially owns 36,622 shares of Repligen common stock directly.

What derivative security is involved in this Repligen Corp (RGEN) Form 4?

The filing involves a stock option (right to buy) with an exercise price of $26.12, relating to 3,366 shares of Repligen common stock.

When does the reported Repligen Corp (RGEN) stock option expire?

The stock option reported in the filing has an expiration date of 05/11/2026.

Is the Repligen Corp (RGEN) stock option reported in this filing vested?

Yes. The explanation states that this option is fully vested and exercisable.