X0306 4 2017-07-21 0 0001113148 INFINITY PHARMACEUTICALS, INC. INFI 0001680745 Tasker Seth A C/O INFINITY PHARMACEUTICALS, INC., 784 MEMORIAL DRIVE CAMBRIDGE MA 02139 0 1 0 0 General Counsel Common Stock 2017-07-21 4 A 0 8916 0.00 A 17833 D Common Stock 6756.49 I 401(k) Represents shares from a grant of performance-based restricted stock on July 22, 2016. Upon the determination by the Compensation Committee of our Board of Directors, such shares vested on July 21, 2017. The number of shares in column 5 represents a net amount of shares issued to the reporting person after the issuer withheld 4,284 shares in order to satisfy the reporting person's income tax withholding obligation. /s/ Seth A. Tasker 2017-07-24