Repligen (RGEN) COO logs PSU share grant and tax withholding on Form 4

Rhea-AI Filing Summary

Repligen Corp Chief Operating Officer James Bylund reported routine equity compensation activity. He acquired 125 shares of common stock at no cost upon the release of a Performance Stock Unit award tied to pre-established performance criteria, and 62 shares were withheld to cover related tax obligations. After these transactions, he directly holds 17,672 common shares.

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider Bylund James

Role Chief Operating Officer

Type	Security	Shares	Price	Value
Grant/Award	Common Stock	125	$0.00	--
Tax Withholding	Common Stock	62	$125.84	$8K

Holdings After Transaction: Common Stock — 17,734 shares (Direct)

Footnotes (1)

1. Represents 125 shares issued pursuant to a Performance Stock Unit ("PSU") award granted to the Issuer on January 1, 2025. The Compensation Committee authorized the issuance of the underlying shares based upon the Issuer's achievement of pre-established performance criteria set forth in the PSU award. Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations of the reporting person that arose upon the release of the performance stock units.

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
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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^*

Bylund James

(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)

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

3. Date of Earliest Transaction (Month/Day/Year)
03/04/2026

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	03/04/2026		A		125(1)	A	$0	17,734	D
Common Stock	03/04/2026		F		62(2)	D	$125.84	17,672	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

Explanation of Responses:

1. Represents 125 shares issued pursuant to a Performance Stock Unit ("PSU") award granted to the Issuer on January 1, 2025. The Compensation Committee authorized the issuance of the underlying shares based upon the Issuer's achievement of pre-established performance criteria set forth in the PSU award.

2. Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations of the reporting person that arose upon the release of the performance stock units.

	/s/ Jennifer Carmichael (Attorney in Fact)	03/05/2026
	** 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.

FAQ

What insider transactions did RGEN executive James Bylund report?

James Bylund reported a grant of 125 Repligen common shares from a Performance Stock Unit award and a 62-share tax-withholding disposition. These non-market transactions reflect equity compensation and related tax settlement, not open-market buying or selling activity.

How many Repligen (RGEN) shares does James Bylund hold after this Form 4?

After the reported transactions, James Bylund directly holds 17,672 Repligen common shares. This balance reflects the 125-share PSU-related issuance and the 62 shares withheld by the company to satisfy tax obligations arising from the performance stock unit release.

What is the nature of the 125 Repligen shares acquired by James Bylund?

The 125 Repligen shares were issued under a Performance Stock Unit award granted January 1, 2025. The Compensation Committee authorized these shares after the company achieved pre-established performance criteria set in the PSU, resulting in a grant at no cash cost to Bylund.

Why were 62 Repligen (RGEN) shares disposed of in this Form 4?

The 62 Repligen shares reflect withholding by the company to cover James Bylund’s tax obligations when his performance stock units were released. This is a tax-withholding disposition, not an open-market sale, and is common in equity compensation settlements.

What roles and titles does James Bylund hold at Repligen (RGEN)?

James Bylund serves as Chief Operating Officer of Repligen. As an officer, his equity compensation and related share transactions, like performance stock unit releases and tax-withholding dispositions, must be reported publicly on Form 4 to provide transparency into his ownership changes.

Was cash paid for the 125 Repligen shares issued to James Bylund?

No cash was paid for the 125 Repligen shares, which were issued at a price of $0.0000 per share. They came from a Performance Stock Unit award that vested based on pre-established company performance criteria approved by the Compensation Committee.