X0508 4 2024-03-31 0 0001819928 DoubleVerify Holdings, Inc. DV 0001709574 Zagorski Mark C/O DOUBLEVERIFY HOLDINGS, INC. 462 BROADWAY NEW YORK NY 10013 1 1 0 0 Chief Executive Officer 0 Common Stock 2024-03-31 4 M 0 10417 0.00 A 388366 D Common Stock 2024-03-31 4 F 0 5761 35.16 D 382605 D Restricted Stock Units 2024-03-31 4 M 0 10417 0.00 D Common Stock 10417 20832 D Each restricted stock unit ("RSU") was granted on July 28, 2020 and represents a right to receive one share of common stock on a one-to-one basis. 37.5% of the RSUs vested and were settled on April 20, 2021, upon the initial public offering (the "IPO") of common stock of DoubleVerify Holdings, Inc. The remaining RSUs vest on the original vesting schedule as though the IPO had not occurred, subject to Mr. Zagorksi's continued employment through the applicable vesting date. Represents shares withheld to satisfy tax obligations in connection with the vesting of 10,417 RSUs on March 31, 2024. 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 2024-04-02