X0306 4 2021-07-21 0 0001819928 DoubleVerify Holdings, Inc. DV 0001709574 Zagorski Mark C/O DOUBLEVERIFY HOLDINGS, INC. 233 SPRING STREET NEW YORK NY 10013 1 1 0 0 Chief Executive Officer Common Stock 2021-07-21 4 M 0 86581 0.00 A 333786 D Common Stock 2021-07-21 4 F 0 49681 36.25 D 284105 D Restricted Stock Units 2021-07-21 4 M 0 86581 0.00 D 2021-07-21 Common Stock 86581 0 D The total was increased by one share due to an administrative calculation error due to rounding of the vested amount. Each restricted stock unit was granted on July 28, 2020 and represents a right to receive one share of common stock on a one-for-one basis. The restricted stock units fully vested on July 21, 2021. Represents shares withheld to satisfy tax obligations in connection with the vesting of 86,581 restricted stock units on July 21, 2021. Restricted stock units convert into common stock on a one-for-one basis. /s/ Andrew E. Grimmig, as Attorney-in-Fact for Mark S. Zagorski 2021-07-22