X0306 4 2016-11-14 0 0001629137 Global Blood Therapeutics, Inc. GBT 0001488495 Third Rock Ventures II, L.P. C/O THIRD ROCK VENTURES, LLC 29 NEWBURY STREET, 3RD FLOOR BOSTON MA 02116 0 0 1 0 0001614061 Third Rock Ventures GP II, L.P. 29 NEWBURY STREET, 3RD FLOOR BOSTON MA 02116 0 0 1 0 0001614073 TRV GP II, LLC 29 NEWBURY STREET, 3RD FLOOR BOSTON MA 02116 0 0 1 0 0001569705 Third Rock Ventures III, L.P. C/O THIRD ROCK VENTURES, LLC, 29 NEWBURY STREET, 3RD FLOOR BOSTON MA 02116 0 0 1 0 0001637300 Third Rock Ventures GP III, L.P. 29 NEWBURY STREET, 3RD FLOOR BOSTON MA 02116 0 0 1 0 0001637299 TRV GP III, LLC 29 NEWBURY STREET, 3RD FLOOR BOSTON MA 02116 0 0 1 0 0001180428 LEVIN MARK J 29 NEWBURY STREET, 3RD FLOOR BOSTON MA 02116 0 0 1 0 0001192595 TEPPER ROBERT I 29 NEWBURY STREET, 3RD FLOOR BOSTON MA 02116 0 0 1 0 0001192603 STARR KEVIN P 29 NEWBURY STREET, 3RD FLOOR BOSTON MA 02116 0 0 1 0 Common Stock 2016-11-14 4 S 0 1000000 19.36 D 9475191 D Common Stock 2016-11-14 4 S 0 1000000 19.36 D 1285713 D Common Stock 108957 D Common Stock 108955 D Common Stock 108956 D These shares are directly held by Third Rock Ventures II, L.P. ("TRV II"). The general partner of TRV II is Third Rock Ventures GP II, L.P. ("TRV GP II"). The general partner of TRV GP II is TRV GP II, LLC ("TRV GP II LLC"). The individual managers of TRV GP II LLC are Mark Levin ("Levin"), Kevin Starr ("Starr") and Dr. Robert Tepper ("Tepper"). Each of TRV GP II, TRV GP II LLC, Levin, Starr and Tepper disclaims beneficial ownership of the shares except to the extent of its or his pecuniary interest therein, if any, and this report shall not be deemed an admission that it or he is the beneficial owner of such shares. These shares are directly held by Third Rock Ventures III, L.P. ("TRV III"). The general partner of TRV III is Third Rock Ventures GP III, L.P. ("TRV GP III"). The general partner of TRV GP III is TRV GP III, LLC ("TRV GP III LLC"). The individual managers of TRV GP III LLC are Levin, Starr and Tepper. Each of TRV GP III, TRV GP III LLC, Levin, Starr and Tepper disclaims beneficial ownership of the shares except to the extent of its or his pecuniary interest therein, if any, and this report shall not be deemed an admission that it or he is the beneficial owner of such shares. Includes shares received by Levin, Starr and Tepper, as applicable, in a distributions-in-kind by TRV II on November 3, 2016, which distribution was made in accordance with the exemption afforded by Rule 16a-13 of the Securities Exchange Act of 1934, as amended. These shares are directly held by Levin. These shares are directly held by Starr. These shares are directly held by Tepper. /s/ Kevin Gillis, Chief Financial Officer of TRV GP II, LLC, general partner of Third Rock Ventures GP II, L.P., general partner of Third Rock Ventures II, L.P. 2016-11-16 /s/ Kevin Gillis, Chief Financial Officer of TRV GP II, LLC, general partner of Third Rock Ventures GP II, L.P. 2016-11-16 /s/ Kevin Gillis, Chief Financial Officer of TRV GP II, LLC 2016-11-16 /s/ Kevin Gillis, Chief Financial Officer of TRV GP III, LLC, general partner of Third Rock Ventures GP III, L.P., general partner of Third Rock Ventures III, L.P. 2016-11-16 /s/ Kevin Gillis, Chief Financial Officer of TRV GP III, LLC, general partner of Third Rock Ventures GP III, L.P. 2016-11-16 /s/ Kevin Gillis, Chief Financial Officer of TRV GP III, LLC 2016-11-16 /s/ Kevin Gillis by power of attorney for Mark Levin 2016-11-16 /s/ Kevin Gillis by power of attorney for Kevin Starr 2016-11-16 /s/ Kevin Gillis by power of attorney for Dr. Robert Tepper 2016-11-16