Brian Robb Douglass - 31 Dec 2025 Form 3 Insider Report for REPLIGEN CORP (RGEN)

Role
CHIEF PRODUCT OFFICER
Signature
/s/ Meghan Stapleton (Attorney in Fact)
Issuer symbol
RGEN
Transactions as of
31 Dec 2025
Net transactions value
$0
Form type
3
Filing time
12 Jan 2026, 16:30:14 UTC
Next filing
03 Mar 2026
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Douglass Brian Robb CHIEF PRODUCT OFFICER C/O REPLIGEN CORPORATION, 41 SEYON ST., BLDG 1, STE 100, WALTHAM /s/ Meghan Stapleton (Attorney in Fact) 12 Jan 2026 0002104618

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
holding RGEN Common Stock 6,252 31 Dec 2025 Direct F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
holding RGEN Stock Option (Right to Buy) 31 Dec 2025 Common Stock 2,980 $167.72 Direct F2
holding RGEN Stock Option (Right to Buy) 31 Dec 2025 Common Stock 7,020 $167.72 Direct F3
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Represent restricted stock units that were awarded to represent a contingent right to receive one share of Repligen Corporation's Common Stock. The restricted stock units may be settled only by delivering shares of Repligen Corporation's Common Stock. 4,000 of the restricted stock units were granted on May 7, 2024 and vest in equal installments over a five-year period with each such vesting date occurring on the anniversary of the grant date. 2,252 of the restricted stock units were granted on March 1, 2025 and vest in equal installments over a four-year period with each such vesting date occurring on the anniversary of the grant date.
F2 The stock option was granted on May 7, 2024 and vest in equal installments over a five-year period with such vesting date occurring on the anniversary of the grant date. 596 shares have vested and the remaining shares will vest in equal installments on May 7, 2026, May 7, 2027, May 7, 2028 and May 7, 2029.
F3 The stock option was granted on May 7, 2024 and vest in equal installments over a five-year period with such vesting date occurring on the anniversary of the grant date. 1,404 shares have vested and the remaining shares will vest in equal installments on May 7, 2026, May 7, 2027, May 7, 2028 and May 7, 2029.

Remarks:

Exhibit 24.1: Power of Attorney