X0306 4 2017-03-02 0 0001629137 Global Blood Therapeutics, Inc. GBT 0001192591 HOMCY CHARLES J C/O GLOBAL BLOOD THERAPEUTICS, INC. 400 EAST JAMIE COURT, SUITE 101 SOUTH SAN FRANCISCO CA 94080 1 0 0 0 Common Stock 2017-03-02 4 S 0 0 0.00 D 0 I See Footnote Common Stock 2017-03-02 4 S 0 0 0.00 D 0 I See Footnote Common Stock 237728 D Common Stock 1600 I Trust On March 2, 2017, Third Rock Ventures II, L.P. ("TRV II") sold 1,000,000 shares of Common Stock of the Issuer. The shares were sold in one execution at a price per share of $25.50. After the transaction referenced in note (1), TRV II owned 6,475,191 shares. The reporting person is a partner of Third Rock Ventures GP II, L.P., which is the general partner of TRV II. The reporting person disclaims beneficial ownership over the shares held by TRV II, except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that he is the beneficial owner of such shares. On March 2, 2017, Third Rock Ventures III, L.P. ("TRV III") sold 1,000,000 shares of Common Stock of the Issuer. The shares were sold in one execution at a price per share of $25.50. After the transaction referenced in note (4), TRV III owned 285,713 shares. The reporting person is a partner of Third Rock Ventures GP III, L.P., which is the general partner of TRV III. The reporting person disclaims beneficial ownership over the shares held by TRV III, except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that he is the beneficial owner of such shares. /s/ Matt Krause, attorney-in-fact 2017-03-06