X0306 4 2022-11-03 0 0001861795 Definitive Healthcare Corp. DH 0001947395 Maack Jonathan C/O DEFINITIVE HEALTHCARE CORP. 492 OLD CONNECTICUT PATH, SUITE 401 FRAMINGHAM MA 01701 0 1 0 0 President Class A Common Stock 2022-11-03 4 A 0 546303 0.00 A 546303 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. The RSUs vest over a four-year period, with 25% of the RSUs vesting on November 3, 2023, followed by quarterly vesting of 6.25% every three months thereafter over the subsequent three years, in each case subject to the Reporting Person's continued service with the Issuer through each such vesting date. By:/s/ David Samuels, as attorney in fact 2022-11-07