X0306 4 2021-01-12 0 0001326110 NantKwest, Inc. NK 0001674905 Nelson Sonja C/O NANTKWEST, INC. 3530 JOHN HOPKINS COURT SAN DIEGO CA 92121 0 1 0 0 Chief Financial Officer Common Stock 2021-01-12 4 M 0 11364 3.07 A 31774 D Common Stock 2021-01-12 4 S 0 16364 15.00 D 15410 D Stock Option (right to buy) 3.07 2021-01-12 4 M 0 11364 0.00 D 2028-08-27 Common Stock 11364 165907 D The sale of shares reported on this Form 4 was effected pursuant to a Rule 10b5-1 trading plan entered into by the reporting person on September 4, 2020. Subject to the award recipient's continuing to be a Service Provider (as defined in the 2015 Equity Incentive Plan) through each applicable vesting date, the option shall vest as follows: twenty five percent (25%) of the shares subject to the option shall vest and become exercisable on August 27, 2019, and thereafter the remaining shares subject to the option shall vest and become exercisable in equal monthly installments over thirty six (36) months, such that the option will be fully vested and exercisable on August 27, 2022. /s/ Sonja Nelson 2021-01-13