X0508 4 2026-03-12 0001819928 DoubleVerify Holdings, Inc. DV 0001709574 Zagorski Mark C/O DOUBLEVERIFY HOLDINGS, INC. 462 BROADWAY NEW YORK NY 10013 1 1 Chief Executive Officer 0 Common Stock 2026-03-15 4 M 0 22919 0 A 511505 D Common Stock 2026-03-15 4 F 0 12675 10.21 D 498830 D Common Stock 2026-03-15 4 M 0 60609 0 A 559439 D Common Stock 2026-03-15 4 F 0 33517 10.21 D 525922 D Common Stock 2026-03-15 4 M 0 15219 0 A 541141 D Common Stock 2026-03-15 4 F 0 6724 10.21 D 534417 D Common Stock 2026-03-15 4 M 0 2757 0 A 537174 D Common Stock 2026-03-15 4 F 0 1112 10.21 D 536062 D Common Stock 2026-03-15 4 M 0 7802 0 A 543864 D Common Stock 2026-03-15 4 F 0 3145 10.21 D 540719 D Restricted Stock Units 2026-03-12 4 A 0 275000 0 A Common Stock 275000 275000 D Restricted Stock Units 2026-03-15 4 M 0 22919 0 D Common Stock 22919 252081 D Performance Stock Units 2026-03-15 4 M 0 60609 0 D Common Stock 60609 84849 D Restricted Stock Units 2026-03-15 4 M 0 15219 0 D Common Stock 15219 167409 D Performance Stock Units 2026-03-15 4 M 0 2757 0 D Common Stock 2757 8271 D Restricted Stock Units 2026-03-15 4 M 0 7802 0 D Common Stock 7802 54609 D Restricted Stock Units 2026-03-15 4 M 0 9375 0 D Common Stock 9375 28125 D Each restricted stock unit was granted on March 12, 2026. 8.33% of the restricted stock units vested and were settled on March 15, 2026 (the "2026 Vesting Date"), and the remainder of the restricted stock units vest and settle at a rate of 8.33% on each quarterly anniversary of the 2026 Vesting Date. Represents shares withheld to satisfy tax withholding obligations in connection with the vesting of restricted stock units. Each performance stock unit was granted on March 13, 2025. 41.67% of the earned shares vested and were settled on the 2026 Vesting Date, and the remainder of the earned shares vest and settle at a rate of 8.33% on each quarterly anniversary of the 2026 Vesting Date. Represents shares withheld to satisfy tax withholding obligations in connection with the vesting of performance stock units. Each restricted stock unit was granted on March 13, 2025. 6.25% of the restricted stock units vested and were settled on March 15, 2025 (the "2025 Vesting Date"), and the remainder of the restricted stock units vest at a rate of 6.25% on each quarterly anniversary of the 2025 Vesting Date. Each performance stock unit "PSU" was granted on December 19, 2023. 41.67% of the earned shares vested and were settled on the 2025 Vesting Date, and the remainder of the earned shares vest at a rate of 8.33% on each quarterly anniversary of the 2025 Vesting Date. Each restricted stock unit was 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. Restricted stock units convert into common stock on a one-for-one basis. The restricted stock units were granted on March 12, 2026. 8.33% of the restricted stock units vest and settle on March 15, 2026, and the remainder of the restricted stock units vest and settle at a rate of 8.33% on each quarterly anniversary of the 2026 Vesting Date. Performance stock units convert into common stock on a one-for-one basis. Each performance stock unit was granted on December 19, 2023. 41.67% of the earned shares vested and were settled on the 2025 Vesting Date, and the remainder of the earned shares vest and settle at a rate of 8.33% on each quarterly anniversary of the 2025 Vesting Date. As reported previously, vested shares will be delivered to the reporting person as soon as administratively feasible following his separation from service with the Issuer. Each restricted stock unit was granted on December 12, 2022. 6.25% of the restricted stock units vested 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. /s/ Andrew E. Grimmig, as Attorney-in-Fact for Mark S. Zagorski 2026-03-16