X0609 4 2026-09-15 0001819928 DoubleVerify Holdings, Inc. DV 0002104368 Mougis Steven John false C/O DOUBLEVERIFY HOLDINGS, INC. 462 BROADWAY NEW YORK NY 10013 1 Global Chief Comm. Officer 0 Common Stock 2026-09-15 4 M 0 9376 0 A 104536 D Common Stock 2026-09-15 4 F 0 4787 13.50 D 99749 D Common Stock 2026-09-15 4 M 0 841 0 A 100590 D Common Stock 2026-09-15 4 F 0 430 13.50 D 100160 D Common Stock 2026-09-15 4 M 0 3171 0 A 103331 D Common Stock 2026-09-15 4 F 0 1619 13.50 D 101712 D Common Stock 2026-09-15 4 M 0 27056 0 A 128768 D Common Stock 2026-09-15 4 F 0 13813 13.50 D 114955 D Common Stock 2026-09-15 4 M 0 251 0 A 115206 D Common Stock 2026-09-15 4 F 0 129 13.50 D 115077 D Common Stock 2026-09-15 4 M 0 2125 0 A 117202 D Common Stock 2026-09-15 4 F 0 1085 13.50 D 116117 D Common Stock 2026-09-15 4 M 0 1143 0 A 117260 D Common Stock 2026-09-15 4 F 0 584 13.50 D 116676 D Restricted Stock Units 2026-09-15 4 M 0 9376 0 D Common Stock 9376 84372 D Performance Stock Units 2026-09-15 4 M 0 841 0 D Common Stock 841 4208 D Restricted Stock Units 2026-09-15 4 M 0 3171 0 D Common Stock 3171 31705 D Restricted Stock Units 2026-09-15 4 M 0 27056 0 D Common Stock 27056 54112 D Performance Stock Units 2026-09-15 4 M 0 251 0 D Common Stock 251 251 D Restricted Stock Units 2026-09-15 4 M 0 2125 0 D Common Stock 2125 12748 D Restricted Stock Units 2026-09-15 4 M 0 1143 0 D Common Stock 1143 2286 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 31, 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 31, 2025. 6.25% of the restricted stock units vested and settled on June 15, 2025 (the "2025 Vesting Date"), and the remainder of the restricted stock units vest and settle at a rate of 6.25% on each quarterly anniversary of the 2025 Vesting Date. Each restricted stock unit was granted on March 13, 2025. 12.5% of the restricted stock units vested and were settled on the 2025 Vesting Date, and the remainder of the restricted stock units vest and settle at a rate of 12.5% on each quarterly anniversary of the 2025 Vesting Date. Each performance stock unit was granted on March 15, 2024. 41.67% of the earned shares vested and were settled on March 15, 2025 (the "2025 PSU 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 PSU Vesting Date. Each restricted stock unit was granted on March 15, 2024. 6.25% of the restricted stock units vested and settled on June 15, 2024 (the "2024 Vesting Date"), and the remainder of the restricted stock units vest and settle at a rate of 6.25% on each quarterly anniversary of the 2024 Vesting Date. Each restricted stock unit was granted on March 15, 2023. 6.25% of the restricted stock units vested and settled on June 15, 2023 (the "2023 Vesting Date") and the remainder of the restricted stock units vest and settle at a rate of 6.25% on each quarterly anniversary of the 2023 Vesting Date. Restricted stock units convert into common stock on a one-for-one basis. Performance stock units convert into common stock on a one-for-one basis. /s/ Andrew E. Grimmig, as Attorney-in-Fact for Steven J. Mougis 2026-09-17