1. The securities reported represent shares of common stock of DoubleVerify Holdings, Inc. (the "Issuer") acquired by Providence Equity Partners L.L.C. ("PEP LLC") after the transfer of the Issuer's common stock from Lucy Dobrin and R. Davis Noell. Lucy Dobrin and R. Davis Noell received the shares as board compensation for their service on the Issuer's board of directors and transferred the shares to PEP LLC pursuant to the terms of PEP LLC's internal policy.

2. R. Davis Noell, J. David Phillips, Karim A. Tabet, Andrew A. Tisdale and Michael J. Dominguez may be deemed to exercise voting and investment power over, and thus may be deemed to beneficially own, the securities held by PEP LLC. Each of R. Davis Noell, J. David Phillips, Karim A. Tabet, Andrew A. Tisdale and Michael J. Dominguez hereby disclaims beneficial ownership of the shares held by PEP LLC, except to the extent of its or his pecuniary interest therein, and this form shall not be construed as an admission that any such reporting person is the beneficial owner of any of the securities reported on this form.

3. The securities reported are held directly by PEP LLC and may be deemed to be beneficially owned by R. Davis Noell, J. David Phillips, Karim A. Tabet, Andrew A. Tisdale and Michael J. Dominguez due to their control of PEP LLC.

4. The record and other beneficial owners of the reported securities have separately filed Form 4s.

5. The securities reported represent shares of common stock of the Issuer held by Providence VII U.S. Holdings L.P. ("Providence VII").

6. The securities reported are held directly by Providence VII and may be deemed to be beneficially owned by Providence Equity GP VII-A L.P. ("Providence GP") because Providence GP is the general partner of Providence VII. R. Davis Noell, J. David Phillips, Karim A. Tabet, Andrew A. Tisdale and Michael J. Dominguez control Providence Holdco (International) GP Ltd. ("Holdco"), which is the general partner of Providence Fund Holdco (International) L.P. Providence Fund Holdco (International) L.P. is the general partner of PEP VII-A International Ltd., which is the general partner of Providence GP.

7. R. Davis Noell, J. David Phillips, Karim A. Tabet, Andrew A. Tisdale and Michael J. Dominguez may be deemed to exercise voting and investment power over, and thus may be deemed to beneficially own, the securities held by Providence VII due to their relationships with Holdco. Each of Providence GP, R. Davis Noell, J. David Phillips, Karim A. Tabet, Andrew A. Tisdale and Michael J. Dominguez hereby disclaims beneficial ownership of the shares held by Providence VII, except to the extent of its or his pecuniary interest therein, and this form shall not be construed as an admission that any such reporting person is the beneficial owner of any of the securities reported on this form.

8. The securities reported represent shares of common stock of the Issuer held by Providence Butternut Co-Investment L.P. ("Providence Butternut").

9. R. Davis Noell, J. David Phillips, Karim A. Tabet, Andrew A. Tisdale and Michael J. Dominguez may be deemed to exercise voting and investment power over, and thus may be deemed to beneficially own, the securities held by Providence Butternut due to their relationships with Holdco. Each of Providence GP, R. Davis Noell, J. David Phillips, Karim A. Tabet, Andrew A. Tisdale and Michael J. Dominguez hereby disclaims beneficial ownership of the shares held by Providence Butternut, except to the extent of its or his pecuniary interest therein, and this form shall not be construed as an admission that any such reporting person is the beneficial owner of any of the securities reported on this form.

10. The securities reported are held directly by Providence Butternut and may be deemed to be beneficially owned by Providence GP because Providence GP is the general partner of Providence Butternut. R. Davis Noell, J. David Phillips, Karim A. Tabet, Andrew A. Tisdale and Michael J. Dominguez control Holdco, which is the general partner of Providence Fund Holdco (International) L.P. Providence Fund Holdco (International) L.P. is the general partner of PEP VII-A International Ltd., which is the general partner of Providence GP.

11. Restricted stock units convert into common stock on a one-for-one basis.

12. Represents time-based restricted stock units granted on May 21, 2025 pursuant to the annual equity grant under DoubleVerify Holdings, Inc.'s non-employee director compensation program. The restricted stock units vest on the earlier of (i) May 21, 2026 and (ii) the date of DoubleVerify Holdings, Inc.'s 2026 Annual Meeting of Stockholders, subject to Mr. Noell's continued services.