X0306 4 2018-07-23 1 0001434418 CONSTELLATION PHARMACEUTICALS INC CNST 0001534261 Casdin Capital, LLC 1350 AVENUE OF THE AMERICAS, SUITE 2405 NEW YORK NY 10019 0 0 1 0 0001534265 Casdin Partners Master Fund, L.P. C/O CASDIN CAPITAL LLC 1350 AVENUE OF THE AMERICAS, SUITE 2405 NEW YORK NY 10019 0 0 1 0 0001534260 Casdin Partners GP, LLC C/O CASDIN CAPITAL LLC 1350 AVENUE OF THE AMERICAS, SUITE 2405 NEW YORK NY 10019 0 0 1 0 0001534264 Casdin Eli C/O CASDIN CAPITAL LLC 1350 AVENUE OF THE AMERICAS, SUITE 2405 NEW YORK NY 10019 0 0 1 0 0001730779 Casdin Venture Opportunities Fund, L.P. C/O CASDIN CAPITAL LLC 1350 AVENUE OF THE AMERICAS, SUITE 2405 NEW YORK NY 10019 0 0 1 0 0001746899 CASDIN VENTURE OPPORTUNITIES FUND GP, LLC C/O CASDIN CAPITAL LLC 1350 AVENUE OF THE AMERICAS, SUITE 2405 NEW YORK NY 10019 0 0 1 0 Common Stock 2018-07-23 4 C 0 345783 A 345783 I See footnote Common Stock 2018-07-23 4 P 0 266667 15.00 A 612450 I See footnote Common Stock 2018-07-23 4 C 0 158960 A 158960 I See footnote Series E Preferred Stock 2018-07-23 4 C 0 1333333 0.00 D Common Stock 155716 0 I See footnote Series E-1 Preferred Stock 2018-07-23 4 C 0 342435 0.00 D Common Stock 31104 0 I See footnote Series F Preferred Stock 2018-07-23 4 C 0 1750000 0.00 D Common Stock 158963 0 I See footnote Series F Preferred Stock 2018-07-23 4 C 0 1750000 0.00 D Common Stock 158960 0 I See footnote On July 23, 2018, the Series E-1 and Series F Preferred Stock converted into Common Stock on a 11.009-for-one basis, and the Series E Preferred Stock converted into Common Stock on a 8.56256-for-one basis, upon the closing of the Issuer's initial public offering without payment of consideration. The Series E, Series E-1 and Series F Preferred Stock were convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial pubic offering. The shares had no expiration date. These securities are owned directly by Casdin Partners Master Fund, LP and may be deemed to be indirectly beneficially owned by (i) Casdin Capital, LLC, the investment adviser to Casdin Partners Master Fund, LP, (ii) Casdin Partners GP, LLC, the general partner of Casdin Partners Master Fund LP, and (ii) Eli Casdin, the managing member of Casdin Capital, LLC and Casdin Partners GP, LLC. These securities are owned directly by Casdin Venture Opportunities Fund, LP and may be deemed to be indirectly beneficially owned by (i) Casdin Capital, LLC, the investment adviser to Casdin Venture Opportunities Fund, LP, (ii) Casdin Venture Opportunities Fund GP, LLC, the general partner of Casdin Venture Opportunities Fund, LP, and (ii) Eli Casdin, the managing member of Casdin Capital, LLC and Casdin Venture Opportunities Fund GP, LLC. Casdin Capital, LLC, By: Eli Casdin, Managing Member, /s/ Eli Casdin 2018-07-23 Casdin Partners Master Fund, LP, By: Casdin Partners GP, LLC, General Partner, By: Eli Casdin, Managing Member, /s/ Eli Casdin 2018-07-23 Casdin Partners GP, LLC, By: Eli Casdin, Managing Member, /s/ Eli Casdin 2018-07-23 Eli Casdin, /s/ Eli Casdin 2018-07-23 Casdin Venture Opportunities Fund, LP, Casdin Venture Opportunities Fund GP, LLC, General Partner, By: Eli Casdin, Managing Member, /s/ Eli Casdin 2018-07-23 Casdin Venture Opportunities Fund GP, LLC, By: Eli Casdin, Managing Member, /s/ Eli Casdin 2018-07-23