X0508 4 2024-03-15 0 0001819928 DoubleVerify Holdings, Inc. DV 0001854086 Allais Nicola T C/O DOUBLEVERIFY HOLDINGS, INC. 462 BROADWAY NEW YORK NY 10013 0 1 0 0 Chief Financial Officer 1 Common Stock 2024-03-15 4 M 0 2489 0.00 A 69798 D Common Stock 2024-03-15 4 F 0 1004 33.09 D 68794 D Common Stock 2024-03-15 4 M 0 4063 0.00 A 72857 D Common Stock 2024-03-15 4 F 0 1638 33.09 D 71219 D Common Stock 2024-03-15 4 M 0 3034 0.00 A 74253 D Common Stock 2024-03-15 4 F 0 1223 33.09 D 73030 D Common Stock 2024-03-18 4 M 0 5364 2.01 A 78394 D Common Stock 2024-03-18 4 S 0 5364 32.7961 D 73030 D Restricted Stock Units 2024-03-15 4 M 0 2489 0.00 D Common Stock 2489 17421 D Restricted Stock Units 2024-03-15 4 M 0 4063 0.00 D Common Stock 4063 44685 D Restricted Stock Units 2024-03-15 4 M 0 3034 0.00 D Common Stock 3034 45510 D Options (Rights to Buy) 2.01 2024-03-18 4 M 0 5364 0.00 D 2028-01-04 Common Stock 5364 384836 D The restricted stock units were granted on December 10, 2021. 6.25% of the restricted stock units vested and were settled on March 15, 2022 (the "2022 Vesting Date"), and the remainder of the restricted stock units vest at a rate of 6.25% on each quarterly anniversary of the 2022 Vesting Date. Represents shares withheld to satisfy tax obligations in connection with the vesting of 2,489 restricted stock units on March 15, 2024. The restricted stock units were granted on December 12, 2022. 6.25% of the restricted stock units vested and were settled on March 15, 2023 (the "2023 Vesting Date"), and the remainder of the restricted stock units vest at a rate of 6.25% on each quarterly anniversary of the 2023 Vesting Date. Represents shares withheld to satisfy tax obligations in connection with the vesting of 4,063 restricted stock units on March 15, 2024. The restricted stock units were granted on December 19, 2023. 6.25% of the restricted stock units vested and were settled on March 15, 2024 (the "2024 Vesting Date"), and the remainder of the restricted stock units vest at a rate of 6.25% on each quarterly anniversary of the 2024 Vesting Date. Represents shares withheld to satisfy tax obligations in connection with the vesting of 3,034 restricted stock units on March 15, 2024. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on November 14, 2023. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $32.71 to $32.96, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth above. Restricted stock units convert into common stock on a one-for-one basis. Represents non-qualified stock options granted on January 4, 2018, 25% of which vested on November 6, 2018 and the remainder of which vested at a rate of 6.25% per quarter thereafter, subject to Mr. Allais's continued employment. The options fully vested on November 6, 2021. /s/ Andrew E. Grimmig, as Attorney-in-Fact for Nicola T. Allais 2024-03-19