Repligen insider plans sale of 5,426 shares

Rule 144 notice reports Olivier Loeillot’s planned sale of 5,426 Repligen common shares from a stock option exercise, plus two earlier sales in the prior three months.

Rhea-AI Filing Summary

REPLIGEN CORP (RGEN) has a notice of proposed sale under Rule 144 filed for the account of Olivier Loeillot. The filing covers a planned sale of 5,426 common shares of Repligen on September 21, 2026, to be delivered from a stock option exercise for cash through Fidelity Brokerage Services LLC.

The notice also lists sales by the same person during the prior three months: 5,426 shares of common stock on August 20, 2026 for an aggregate of $976,680.00, and 3,035 shares on September 4, 2026 for an aggregate of $503,506.50.

Key Figures

Shares proposed for sale: 5,426 shares Shares sold on August 20, 2026: 5,426 shares Aggregate proceeds August 20, 2026 sale: $976,680.00 +3 more

6 metrics

Shares proposed for sale 5,426 shares Common stock of REPLIGEN CORP to be sold on September 21, 2026 under Rule 144

Shares sold on August 20, 2026 5,426 shares Common stock sale by Olivier Loeillot during the prior three months

Aggregate proceeds August 20, 2026 sale $976,680.00 Total consideration for 5,426 Repligen common shares sold by Olivier Loeillot

Shares sold on September 4, 2026 3,035 shares Common stock sale by Olivier Loeillot during the prior three months

Aggregate proceeds September 4, 2026 sale $503,506.50 Total consideration for 3,035 Repligen common shares sold by Olivier Loeillot

Planned sale date September 21, 2026 Date for proposed sale of 5,426 Repligen common shares from stock option exercise

Key Terms

Rule 144, Stock Option Exercise, attorney-in-fact, aggregate

4 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Stock Option Exercise financial

"Common | 09/21/2026 | Stock Option Exercise | Issuer"

A stock option exercise is the act of using a previously granted right to buy shares of a company's stock at a specific, predetermined price by paying that price and receiving the shares. It matters to investors because exercising changes who owns the shares (which can dilute existing ownership), can trigger taxable events and shift potential gains or losses, and affects voting power and the company’s outstanding share count—like turning a voucher into an actual product that becomes part of circulating supply.

attorney-in-fact regulatory

"as attorney-in-fact for Olivier Loeillot"

An attorney-in-fact is the person or entity given legal authority through a power of attorney to act on behalf of another for specific tasks, such as signing documents, voting shares, or handling transactions. For investors, this matters because it lets a trusted representative make timely decisions or complete paperwork when the owner cannot, much like handing keys to someone to run errands on your behalf—so checks on scope and limits of that authority are important.

aggregate financial

"08/20/2026 | 5426 | 976680.00"

A combined total or summary created by adding together multiple parts or data points. Used as a noun and a verb, it means pooling individual items (sales, revenues, assets, transactions, or data) into one overall figure so stakeholders can see the big picture; like pouring many small jars into a single container to measure the total amount. Aggregate figures matter to investors because they show the overall size, trend, or exposure of a business or market rather than the detail of each component.

FAQ

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

What does the Form 144 filing disclose for REPLIGEN CORP (RGEN)?

It discloses a planned sale under Rule 144 for the account of Olivier Loeillot, covering 5,426 shares of Repligen common stock to be sold on September 21, 2026, with shares to be delivered from a stock option exercise for cash.

How many RGEN shares are proposed to be sold in this Form 144?

The filing covers a proposed sale of 5,426 shares of Repligen common stock. These shares are indicated as coming from a stock option exercise dated September 21, 2026, with cash as the form of payment.

What prior sales by Olivier Loeillot in RGEN shares are reported?

The filing reports that Olivier Loeillot sold 5,426 shares of Repligen common stock on August 20, 2026 for an aggregate of $976,680.00, and 3,035 shares on September 4, 2026 for an aggregate of $503,506.50.

Who is handling the proposed sale of RGEN shares under this Form 144?

The proposed sale of 5,426 Repligen common shares is associated with Fidelity Brokerage Services LLC, listed with its Smithfield, Rhode Island address as part of the securities information section.

What is the class of securities covered in this REPLIGEN CORP (RGEN) Form 144?

The Form 144 covers Common stock of REPLIGEN CORP. All transactions listed in the filing, including the proposed sale and the past three-month sales, relate to Repligen common shares traded on Nasdaq.

Who signed the Form 144 related to REPLIGEN CORP (RGEN)?

The Form 144 is signed by /s/ Jennifer Ruchti, described as a duly authorized representative of Fidelity Brokerage Services LLC acting as attorney-in-fact for Olivier Loeillot, with a signature date of September 21, 2026.

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

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Available on EDGAR 09/21/2026 - 03:04 PM Accepted by SEC EDGAR 09/21/2026 - 03:03 PM Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001995525
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	REPLIGEN CORP
SEC File Number	000-14656
Address of Issuer	41 SEYON STREET BUILDING 1, SUITE 100 WALTHAM MASSACHUSETTS 02453
Phone	7814499560
Name of Person for Whose Account the Securities are To Be Sold	Loeillot Olivier
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer
Relationship to Issuer	Director

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Fidelity Brokerage Services LLC 900 Salem Street Smithfield RI 02917	5426	976680.00	56435621	09/21/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	09/21/2026	Stock Option Exercise	Issuer			5426	09/21/2026	Cash

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
Olivier Loeillot 41 Seyon Street Bldg. 1, Suite 100 Waltham MA 02453	Common	08/20/2026	5426	976680.00
Olivier Loeillot 41 Seyon Street Bldg. 1, Suite 100 Waltham MA 02453	Common	09/04/2026	3035	503506.50

144: Remarks and Signature

Remarks
Date of Notice	09/21/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	08/19/2025
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Jennifer Ruchti, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Olivier Loeillot
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)