Repligen (RGEN) director adds 2,434 shares via option exercise

Rhea-AI Filing Summary

REPLIGEN CORP director Glenn P. Muir exercised stock options to acquire 2,434 shares of Common Stock. The options were exercised at $38.76 per share on May 7, 2026, and were fully vested and exercisable. Following the transaction, Muir directly holds 39,056 Common Stock shares. A corresponding derivative entry shows 2,434 Stock Option (Right to Buy) units exercised with an exercise price of $38.76 and an expiration date of May 18, 2027. No share sales or tax-withholding dispositions are reported in this Form 4.

Insider Trade Summary

2,434 shares exercised/converted

Mixed 2 txns

Insider MUIR GLENN P

Role null

Type	Security	Shares	Price	Value
Exercise	Stock Option (Right to Buy)	2,434	$0.00	--
Exercise	Common Stock	2,434	$38.76	$94K

Holdings After Transaction: Stock Option (Right to Buy) — 2,434 shares (Direct, null); Common Stock — 39,056 shares (Direct, null)

Footnotes (1)

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Key Figures

Shares acquired via option exercise: 2,434 shares Option exercise price: $38.76 per share Shares held after transaction: 39,056 shares +2 more

5 metrics

Shares acquired via option exercise 2,434 shares Common Stock acquired through option exercise on May 7, 2026

Option exercise price $38.76 per share Conversion or exercise price for Stock Option (Right to Buy)

Shares held after transaction 39,056 shares Total direct Common Stock holdings following the transaction

Options exercised 2,434 options Stock Option (Right to Buy) units exercised into Common Stock

Option expiration date May 18, 2027 Expiration for the Stock Option (Right to Buy) grant

Key Terms

Stock Option (Right to Buy), derivative security, fully vested and exercisable, Form 4

4 terms

Stock Option (Right to Buy) financial

"The filing lists a derivative security titled "Stock Option (Right to Buy)" covering 2,434 shares."

derivative security financial

"The transaction code description states "Exercise or conversion of derivative security" for the option."

A derivative security is a financial contract whose value comes from the price or performance of something else, such as a stock, bond, commodity, or market index. For investors it acts like an insurance policy or a wager: it can be used to protect against losses, lock in prices, or amplify gains and losses, so it can change a portfolio’s risk and potential return without owning the underlying asset directly.

fully vested and exercisable financial

"A footnote explains, "This option is fully vested and exercisable.""

Form 4 regulatory

"The insider activity is reported in an INSIDER FILING DATA (Form 4) entry for REPLIGEN CORP."

Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.

Form 4 Insider Transactions: What Each Field Means →

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

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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 MASSACHUSETTS 02453

(City) (State) (Zip)

UNITED STATES

(Country)

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)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/07/2026

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

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

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

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	05/07/2026		M		2,434	A	$38.76	39,056	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)	$38.76	05/07/2026		M		2,434		(1)	05/18/2027	Common Stock	2,434	$0.00	2,434	D

Explanation of Responses:

1. This option is fully vested and exercisable.

	/s/ Jennifer Carmichael (Attorney in Fact)	05/08/2026
	** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did REPLIGEN (RGEN) director Glenn P. Muir report?

Director Glenn P. Muir exercised stock options to acquire 2,434 shares of REPLIGEN Common Stock. The transaction used options labeled as Stock Option (Right to Buy), converting derivative securities into directly held shares without any reported share sales.

At what price did Glenn P. Muir exercise REPLIGEN stock options?

Glenn P. Muir exercised his REPLIGEN stock options at an exercise price of $38.76 per share. This price is shown as the conversion or exercise price for 2,434 Stock Option (Right to Buy) units underlying the acquired Common Stock.

How many REPLIGEN shares does Glenn P. Muir hold after this Form 4?

After the reported option exercise, Glenn P. Muir directly holds 39,056 shares of REPLIGEN Common Stock. This total reflects his position following the acquisition of 2,434 shares through exercising fully vested and exercisable options.

Did Glenn P. Muir sell any REPLIGEN shares in this Form 4 filing?

No shares were reported sold in this Form 4. The transactions show only option exercises coded as “M” for derivative exercise or conversion, with no sale codes and no tax-withholding dispositions, indicating purely an acquisition of shares.

What is the status and expiration of the REPLIGEN options Muir exercised?

The filing notes the option was fully vested and exercisable when used. The Stock Option (Right to Buy) covered 2,434 shares with a $38.76 exercise price and carries an expiration date of May 18, 2027, for the original option grant.