Repligen CEO exercises, sells 5,426 shares

Repligen’s CEO and director exercised options for 5,426 shares and sold the same amount under a pre-arranged Rule 10b5-1 trading plan.

Rhea-AI Filing Summary

REPLIGEN CORP (RGEN) reported that its chief executive officer and director, Loeillot Olivier, exercised employee stock options and sold the resulting shares. On September 21, 2026, he exercised options to acquire 5,426 shares of Common Stock at an exercise price of $141.79 per share, then sold 5,426 shares at $180.00 per share. The filing states that these sales were made under a Rule 10b5-1 trading plan adopted on August 19, 2025.

Insider Trade Summary 10b5-1

Exercise and Sale: 5,426 shares ($207K approx. pre-tax spread)

Exercise and Sale 3 txns

Insider Loeillot Olivier

Role Chief Executive Officer

Sold 5,426 shs ($977K)

Approx. gross sale proceeds $977K

Approx. exercise cost $769K

Approx. pre-tax spread $207K

Type	Security	Shares	Price	Value
Exercise	Stock Option (Right to Buy) F1	5,426	$0.00	$0.00
Exercise	Common Stock F1	5,426	$141.79	$769K
Sale	Common Stock F1	5,426	$180.00	$977K

Holdings After Transaction: Stock Option (Right to Buy) — 5,426 contracts (Direct); Common Stock — 48,369 shares (Direct)

Footnotes (1)

1. F1. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 19, 2025.

Key Figures

Shares exercised: 5,426 shares Option exercise price: $141.79 per share Shares sold: 5,426 shares +4 more

7 metrics

Shares exercised 5,426 shares Options exercised into Common Stock on September 21, 2026

Option exercise price $141.79 per share Exercise price for 5,426 shares of Common Stock

Shares sold 5,426 shares Common Stock sold on September 21, 2026

Sale price $180.00 per share Per-share sale price for 5,426 shares of Common Stock

Rule 10b5-1 plan adoption date August 19, 2025 Date the CEO adopted the trading plan used for these sales

Derivative transaction count 1 transaction One reported option exercise involving 5,426 shares

Net shares sold 5,426 shares Netted from one exercise and one sale of the same number of shares

Key Terms

Rule 10b5-1 trading plan, stock option, derivative security

3 terms

Rule 10b5-1 trading plan regulatory

"The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

stock option financial

"Stock Option (Right to Buy) is listed as a derivative security"

A stock option is a contract that gives you the right to buy or sell a company's stock at a specific price within a certain time frame. People use them to potentially make money if the stock's price moves favorably or to protect against losses. It's like holding a coupon that can be used to buy or sell stock at a set price later on.

derivative security financial

"Stock Option (Right to Buy) is reported as a derivative security related to Common Stock"

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.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did RGEN’s CEO report on September 21, 2026?

Loeillot Olivier reported exercising options to acquire 5,426 shares of Repligen Common Stock at $141.79 per share and selling 5,426 shares at $180.00 per share on September 21, 2026, in an exercise-and-sell transaction.

How many Repligen (RGEN) shares did the CEO sell, and at what price?

Loeillot Olivier sold 5,426 shares of Repligen Common Stock at a sale price of $180.00 per share on September 21, 2026, following an option exercise for the same number of shares.

What was the exercise price of the options used by Repligen’s CEO?

The options exercised by Loeillot Olivier had an exercise price of $141.79 per share, covering 5,426 shares of Repligen Common Stock, and were exercised on September 21, 2026.

Was the Repligen (RGEN) CEO’s stock sale under a Rule 10b5-1 trading plan?

Yes. The filing states the sales were effected pursuant to a Rule 10b5-1 trading plan adopted by Loeillot Olivier on August 19, 2025, indicating they followed a pre-arranged schedule.

What is the role of the insider involved in this Repligen (RGEN) Form 4?

The reporting person, Loeillot Olivier, is identified as both a director and the Chief Executive Officer of Repligen Corp in the Form 4 ownership report.

Did the Repligen CEO’s Form 4 involve derivative securities?

Yes. The Form 4 shows the exercise of a stock option, a derivative security, to acquire 5,426 shares of Repligen Common Stock at an exercise price of $141.79 per share before selling the underlying shares.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/22/2026 - 04:08 PM Accepted by SEC EDGAR 09/22/2026 - 04:07 PM Learn about SEC filing dates

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).

X

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/21/2026

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	09/21/2026		M(1)		5,426	A	$141.79	53,795	D
Common Stock	09/21/2026		S(1)		5,426	D	$180	48,369	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)	$141.79	09/21/2026		M(1)			5,426	09/03/2027	09/03/2034	Common Stock	5,426	$0	5,426	D

Explanation of Responses:

1. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 19, 2025.

Remarks:

	/s/ Jennifer Carmichael (Attorney in Fact)	09/22/2026
	** 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)