X0306 4 2016-12-19 0 0001212458 PROOFPOINT INC PFPT 0001527210 Newell Tracey C/O PROOFPOINT, INC. 892 ROSS DRIVE SUNNYVALE CA 94089 0 1 0 0 EVP, Worldwide Sales Common Stock 2016-12-19 4 M 0 3645 29.44 A 30078 D Common Stock 2016-12-19 4 S 0 3545 70.5319 D 26533 D Common Stock 2016-12-19 4 S 0 100 71.09 D 26433 D Non-qualified Stock Option (right to buy) 29.44 2016-12-19 4 M 0 3645 0 D 2023-10-11 Common Stock 3645 29173 D The transactions reported on this Form 4 were effected pursuant to a 10b5-1 trading plan adopted by the reporting person on February 4, 2016. Represents the aggregate of sales effected on the same day at different prices. Represents the weighted average sales price per share. The shares sold at prices ranging from $70 to $70.9725 per share. Full information regarding the number of shares sold at each price shall be provided upon request to the staff of the U.S. Securities and Exchange Commission, the Issuer, or a security holder of the Issuer. The stock option vested as to 1/4th of the total number of shares on August 16, 2014 and thereafter vest as to 1/48th of the total number of shares in equal monthly installments. /s/ Tracey Newell by Michael Yang, Attorney-in-Fact 2016-12-21