X0508 4 2026-02-24 0001861795 Definitive Healthcare Corp. DH 0002052043 Heller Casey C/O DEFINITIVE HEALTHCARE CORP. 492 OLD CONNECTICUT PATH, SUITE 401 FRAMINGHAM MA 01701 false true false false Chief Financial Officer false Class A Common Stock 2026-02-24 4 A false 733301 0 A 2007322 D Represents restricted stock units ("RSUs"), each representing a contingent right to receive one share of the Issuer's Class A Common Stock, par value $0.001, with 25% of the RSUs vesting on March 1, 2027, followed by vesting of 6.25% every three months thereafter over the subsequent three years, subject to the Reporting Person's continued service with the Issuer through each such vesting date. /s/ Jonathan Paris, Attorney-in-Fact 2026-02-26