X0508 4 2025-04-03 0001861795 Definitive Healthcare Corp. DH 0001879507 Krantz Jason Ronald C/O DEFINITIVE HEALTHCARE CORP. 492 OLD CONNECTICUT PATH, SUITE 401 FRAMINGHAM MA 01701 true false true true EXECUTIVE CHAIRMAN 0 Class A Common Stock 2025-04-03 4 A 0 153847 0 A 1125157 D Class A Common Stock 450000 I See footnote 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 100% of the RSUs vesting on April 1, 2026, subject to the Reporting Person's continued service with the Issuer through each such vesting date. Amount beneficially owned in trust by DH Holdings (fka Jason R. Krantz 2009 Trust), of which the Reporting Person is the beneficiary. /s/ Matthew Ruderman, Attorney-in-Fact 2025-04-07