SCHEDULE 13G/A 0002111539 XXXXXXXX LIVE 8 Common Stock, $.01 par value per share 12/31/2025 0000730272 REPLIGEN CORPORATION 759916109 41 Seyon Street Waltham MA 02453 Rule 13d-1(c) Roy T. Eddleman Living Trust X1 0.00 2705689.00 0.00 2705689.00 2705689.00 N 4.81 OO Roy T. Eddleman Charitable Remainder Trust #1 X1 0.00 29604.00 0.00 29604.00 29604.00 N 0.001 OO Roy T. Eddleman Charitable Remainder Trust #2 X1 0.00 0.00 0.00 0.00 0.00 N 0.00 OO REPLIGEN CORPORATION 41 Seyon Street, Waltham, Massachusetts 02453 (i) Roy T. Eddleman Living Trust (Admin) UAD 8/17/2000 (ii) Roy T. Eddleman Charitable Remainder Trust #1 (iii) Roy T. Eddleman Charitable Remainder Trust #2 c/o TroyGould PC, 1801 Century Park East, 16th Floor, Los Angeles, California 90067, Attention: Sherry Davaie. Each reporting person was formed under the laws of the United States. Y Geoffrey Paul, Nereyda Rubio and Anis Garci are the co-trustees of each reporting person. As co-trustees, each co-trustee has investment and voting control over the shares covered by this Schedule and may be deemed to have shared voting power and shared investment power with respect to all such shares. The co-trustees disclaim beneficial ownership of each reporting persons' shares except to the extent of his/her pecuniary interest therein. The percentage ownership information is calculated based upon 56,290,749 shares of common stock of the Issuer issued and outstanding as ofOctober 30, 2025, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on November 4, 2025. See Item 9 of the cover page. 0 2,735,293 0 2,735,293 N Y Y Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. Roy T. Eddleman Living Trust /s/ Nereyda Rubio 02/13/2026 /s/ Anis Garci 02/13/2026 /s/ Geoffrey Paul 02/13/2026 Roy T. Eddleman Charitable Remainder Trust #1 /s/ Nereyda Rubio 02/13/2026 /s/ Anis Garci 02/13/2026 /s/ Geoffrey Paul 02/13/2026 Roy T. Eddleman Charitable Remainder Trust #2 /s/ Nereyda Rubio 02/13/2026 /s/ Anis Garci 02/13/2026 /s/ Geoffrey Paul 02/13/2026