Repligen (RGEN) CEO reports tax-withholding share dispositions in Form 4

Rhea-AI Filing Summary

Repligen Corp Chief Executive Officer Olivier Loeillot reported two Form 4 transactions where shares were withheld to cover taxes on restricted stock units. On February 27, 2026, 344 shares of common stock were disposed of at $128.73 per share, leaving 35,554 shares directly owned. On March 2, 2026, 1,610 shares were disposed of at $124.97 per share, leaving 33,944 shares directly owned. These are tax-withholding dispositions, not open-market sales.

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider Loeillot Olivier

Role Chief Executive Officer

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock	1,610	$124.97	$201K
Tax Withholding	Common Stock	344	$128.73	$44K

Holdings After Transaction: Common Stock — 33,944 shares (Direct)

Footnotes (1)

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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^*

Loeillot Olivier

(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
X	Officer (give title below)		Other (specify below)
	Chief Executive Officer

3. Date of Earliest Transaction (Month/Day/Year)
02/27/2026

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	02/27/2026		F		344(1)	D	$128.73	35,554	D
Common Stock	03/02/2026		F		1,610(1)	D	$124.97	33,944	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 the number of shares withheld by the Issuer to satisfy tax withholding obligations of the reporting person that arose upon the release of restricted stock units.

	/s/ Jennifer Carmichael (Attorney in Fact)	03/03/2026
	** 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 Repligen (RGEN) report for Olivier Loeillot?

Repligen reported two insider transactions for CEO Olivier Loeillot, both coded “F” as tax-withholding dispositions. The issuer withheld shares upon restricted stock unit release to satisfy Loeillot’s tax obligations instead of conducting open-market sales.

How many Repligen shares were disposed of in these Form 4 transactions?

The transactions show dispositions of 344 shares and 1,610 shares of Repligen common stock. Both were designated as tax-withholding events related to restricted stock units, rather than discretionary buying or selling in the open market.

What prices were used for the Repligen (RGEN) tax-withholding share dispositions?

The 344-share tax-withholding disposition used a price of $128.73 per share, and the 1,610-share disposition used $124.97 per share. These prices are used to value the shares withheld to cover Olivier Loeillot’s tax liabilities.

How many Repligen shares does Olivier Loeillot own after these transactions?

After the February 27, 2026 tax-withholding event, Olivier Loeillot directly owned 35,554 Repligen shares. Following the March 2, 2026 tax-withholding disposition, his direct ownership decreased to 33,944 shares, as reported in the Form 4 ownership totals.

Are these Repligen insider transactions open-market sales by the CEO?

No, the transactions are coded “F,” meaning they are tax-withholding dispositions. The issuer withheld shares from restricted stock unit releases to cover Olivier Loeillot’s tax obligations, rather than the CEO selling shares voluntarily in the open market.

What does transaction code “F” mean in the Repligen Form 4 filing?

Transaction code “F” indicates payment of an exercise price or tax liability by delivering securities. In this case, Repligen withheld common shares from Olivier Loeillot’s restricted stock unit releases to satisfy his tax obligations, instead of requiring a separate cash payment.