X0306 4 2021-07-08 0 0001212458 PROOFPOINT INC PFPT 0001027621 FEIBER JONATHAN D 3000 SAND HILL ROAD BLDG 1 SUITE 240 MENLO PARK CA 94025 1 0 0 0 Common Stock 2021-07-08 4 A 0 1137 0.00 A 10871 D Common Stock 2021-07-08 4 A 0 346 0.00 A 11217 D Represents an award of restricted stock units ("RSUs"). 100% of the RSUs will vest on July 8, 2022. Each RSU represents a contingent right to receive one share of the Issuer's common stock upon settlement for no consideration. Represents an award of RSUs. The RSUs vested as to 1/4th of the total number of shares on July 8, 2021. An additional 1/4th of the total number of shares will vest on each of September 30, 2021, December 31, 2021 and March 31, 2022. Each RSU represents a contingent right to receive one share of the Issuer's common stock upon settlement for no consideration. /s/ Jonathan D. Feiber, by Michael Yang, Attorney-in-Fact 2021-07-12