X0306 4 2021-10-07 0 0001861795 Definitive Healthcare Corp. DH 0001390194 Musslewhite Robert W C/O DEFINITIVE HEALTHCARE CORP. 550 COCHITUATE RD FRAMINGHAM MA 01701 1 1 0 0 President Class A Common Stock 2021-10-07 4 A 0 650000 A 650000 D Represents restricted stock units ("RSUs") to receive one share of the Issuer's Class A Common Stock, par value $0.001 as follows: 433,550 RSUs that vest 25% on the one year anniversary of the grant date, followed by quarterly vesting of 6.25% per quarter until fully vested, over the subsequent three years, and 216,450 RSUs that vest 33% on the one year anniversary of the grant date, followed by quarterly vesting of 8.33% per quarter until fully vested, over the subsequent two years, in each case subject to earlier forfeiture or acceleration. /s/ David Samuels, as attorney-in-fact 2021-10-08