X0508 4 2023-08-22 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 2023-08-22 4 M 0 9231 2.01 A 68905 D Common Stock 2023-08-22 4 S 0 9231 33.0712 D 59674 D Common Stock 2023-08-23 4 M 0 9231 2.01 A 68905 D Common Stock 2023-08-23 4 S 0 9231 33.2892 D 59674 D Options (Rights to Buy) 2.01 2023-08-22 4 M 0 9231 0.00 D 2028-01-04 Common Stock 9231 547121 D Options (Rights to Buy) 2.01 2023-08-23 4 M 0 9231 0.00 D 2028-01-04 Common Stock 9231 537890 D The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 23, 2023. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $32.98 to $33.19 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. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $33.22 to $33.38, 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. 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 2023-08-24