X0306 4 2017-12-27 0 0000730272 REPLIGEN CORP RGEN 0001270264 EDDLEMAN ROY T C/O TROYGOULD PC 1801 CENTURY PARK EAST, 16TH FLOOR LOS ANGELES CA 90067 0 0 1 0 Common Stock 2017-12-27 4 G 0 480000 0 D 357518 D Common Stock 2017-12-27 4 G 0 900000 0 D 357518 D Common Stock 4424826 I By trusts On December 27, 2017, the reporting person contributed 480,000 and 900,000 shares, respectively, of RGEN common stock to separate charitable remainder unit trusts of which the reporting person is the trustee and a lifetime beneficiary. The RGEN shares shown are held for the benefit of the reporting person in an escrow account established in connection with the Issuer's acquisition of Spectrum, Inc. on August 1, 2017, and are subject to potential indemnification claims of the Issuer relating to the acquisition. Of the RGEN shares 3,044,826 are owned of record by the Roy T. Eddleman Living Trust UAD 8-7-2000, of which the reporting person is the sole trustee. The reporting person continues to report beneficial ownership of the RGEN shares contributed to the trusts referred to in note (1), but disclaims beneficial ownership of the trusts' shares except to the extent of his pecuniary interest therein. /s/ Istvan Benko, Attorney-in-Fact for Roy T. Eddleman 2017-12-28