X0306 4 2021-02-01 0 0001212458 PROOFPOINT INC PFPT 0001410972 Auvil Paul R. III C/O PROOFPOINT, INC. 892 ROSS DRIVE SUNNYVALE CA 94089 0 1 0 0 Chief Financial Officer Common Stock 2021-02-01 4 M 0 5000 0.00 A 108149 D Common Stock 2021-02-01 4 M 0 4150 0.00 A 112299 D Common Stock 2021-02-01 4 M 0 4000 0.00 A 116299 D Common Stock 2021-02-01 4 M 0 3750 0.00 A 120049 D Common Stock 2021-02-01 4 F 0 7280 130.62 D 112769 D Common Stock 2021-02-02 4 M 0 2500 0.00 A 115269 D Common Stock 2021-02-02 4 M 0 2500 0.00 A 117769 D Common Stock 2021-02-02 4 F 0 2480 134.57 D 115289 D Common Stock 261918 I By family trust Restricted Stock Units 0.00 2021-02-01 4 M 0 5000 0.00 D Common Stock 5000 0 D Restrricted Stock Units 0.00 2021-02-01 4 M 0 4150 0.00 D Common Stock 4150 4150 D Restricted Stock Units 0.00 2021-02-01 4 M 0 4000 0.00 D Common Stock 4000 8000 D Restricted Stock Units 0.00 2021-02-01 4 M 0 3750 0.00 D Common Stock 3750 11250 D Restricted Stock Units 0.00 2021-02-02 4 M 0 2500 0.00 D Common Stock 2500 0 D Restricted Stock Units 0.00 2021-02-02 4 M 0 2500 0.00 D Common Stock 2500 0 D Vesting of restricted stock units ("RSUs") previously granted to the Reporting Person. Exempt transaction pursuant to Section 16b-3(e) - payment of exercise price or tax liability by delivering or withholding securities incident to the receipt, exercise or vesting of a security issued in accordance with Rule 16b-3. All of the shares reported as disposed of in this Form 4 were relinquished by the Reporting Person and cancelled by the Issuer in exchange for the Issuer's agreement to pay federal and state tax withholding obligations of the Reporting Person resulting from the vesting of RSUs. Each RSU represents a contingent right to receive 1 share of the Issuer's Common Stock upon settlement for no consideration. The RSUs vested as to 1/4th of the total number of shares on February 1, 2018 and thereafter will vest as to 1/4th of the total number of shares in equal annual installments. Shares of the Issuer's common stock will be delivered to the Reporting Person following vesting. RSUs do not expire; they either vest or are canceled prior to the vesting date. The RSUs vested as to 1/4th of the total number of shares on February 1, 2019 and thereafter will vest as to 1/4th of the total number of shares in equal annual installments. Shares of the Issuer's common stock will be delivered to the Reporting Person following vesting. The RSUs vested as to 1/4th of the total number of shares on February 1, 2020 and thereafter will vest as to 1/4th of the total number of shares in equal annual installments. Shares of the Issuer's common stock will be delivered to the Reporting Person following vesting. The RSUs vested as to 1/4th of the total number of shares on February 1, 2021 and thereafter will vest as to 1/4th of the total number of shares in equal annual installments. Shares of the Issuer's common stock will be delivered to the Reporting Person following vesting. The performance-based RSUs were earned by the Reporting Person on June 1, 2018 as a result of the Reporting Person having met certain performance criteria. The RSUs vested as to 5/16th of the total number of shares on June 1, 2018, 3/16th of the total number of shares on February 2, 2019, and thereafter vested as to 1/4th of the total number of shares in equal annual installments beginning on February 2, 2020. Shares of the Issuer's common stock will be delivered to the Reporting Person following vesting. /s/ Paul R. Auvil III, by Michael Yang, Attorney-in-Fact 2021-02-03