X0306 4 2020-04-06 1 0001622229 Cogent Biosciences, Inc. COGT 0001735220 CAMPANA DARIO C/O COGENT BIOSCIENCES, INC. 200 CAMBRIDGE PARK DRIVE, SUITE 2500 CAMBRIDGE MA 02140 0 0 1 0 Common Stock 2020-04-06 4 S 0 50080 0.35 D 5045034 I By IPCT Holdings LLC Common Stock 2020-04-07 4 S 0 11400 0.35 D 5033634 I By IPCT Holdings LLC Common Stock 2020-04-08 4 S 0 100 0.351 D 5033534 I By IPCT Holdings LLC Common Stock 2020-04-09 4 S 0 420292 0.3287 D 4613242 I By IPCT Holdings LLC Common Stock 2020-04-14 4 S 0 54967 0.4024 D 4558275 I By IPCT Holdings LLC Common Stock 2020-04-14 4 S 0 44006 0.40 D 4514269 I By IPCT Holdings LLC Common Stock 2020-04-15 4 S 0 82782 0.3841 D 4431487 I By IPCT Holdings LLC Common Stock 2020-04-16 4 S 0 600 0.3826 D 4430887 I By IPCT Holdings LLC Common Stock 2020-04-17 4 S 0 65540 0.3902 D 4365347 I By IPCT Holdings LLC Common Stock 2020-04-20 4 S 0 12606 0.4006 D 4352741 I By IPCT Holdings LLC Common Stock 2020-04-27 4 S 0 242579 0.4032 D 4110162 I By IPCT Holdings LLC Common Stock 2020-04-28 4 S 0 15048 0.4099 D 4095114 I By IPCT Holdings LLC Common Stock 2020-04-29 4 S 0 382927 0.4061 D 3712187 I By IPCT Holdings LLC Common Stock 2020-04-30 4 S 0 75994 0.4021 D 3636193 I By IPCT Holdings LLC Common Stock 2020-05-01 4 S 0 800 0.41 D 3635393 I By IPCT Holdings LLC Common Stock 2020-05-04 4 S 0 4795 0.4006 D 3630598 I By IPCT Holdings LLC Common Stock 2020-05-05 4 S 0 135484 0.4018 D 3495114 I By IPCT Holdings LLC Common Stock 2020-05-06 4 S 0 1800 0.4009 D 3493314 I By IPCT Holdings LLC Common Stock 2020-05-07 4 S 0 100000 0.4143 D 3393314 I By IPCT Holdings LLC Common Stock 2020-05-08 4 S 0 100000 0.4639 D 3293314 I By IPCT Holdings LLC Common Stock 2020-05-11 4 S 0 22281 0.4639 D 3271033 I By IPCT Holdings LLC Common Stock 2020-05-11 4 S 0 77719 0.4524 D 3193314 I By IPCT Holdings LLC Common Stock 2020-05-12 4 S 0 98200 0.4638 D 3095114 I By IPCT Holdings LLC Shares held by IPCT Holdings LLC ("IPCT"). IPCT is fully owned by South Dakota Trust Company, LLC, solely in its capacity as trustee of the Dario Campana Revocable Trust. The Reporting Person is the ultimate beneficial owner of the Dario Campana Revocable Trust, and disclaims beneficial ownership of these shares except to the extent of his pecuniary interest therein. /s/ Amoli Pandya, as Attorney-in-Fact 2020-10-08