X0306 4 2020-06-19 0 0001326110 NantKwest, Inc. NK 0001647994 Simon Barry J. C/O NANTKWEST, INC. 3530 JOHN HOPKINS COURT SAN DIEGO CA 92121 1 1 0 0 See remarks Common Stock 2020-06-19 4 M 0 9337 1.7554 A 3204243 D Common Stock 2020-06-19 4 S 0 13737 9.0003 D 3190506 D Common Stock 2020-06-22 4 M 0 136729 1.7554 A 3327235 D Common Stock 2020-06-22 4 S 0 66263 9.4292 D 3260972 D Common Stock 2020-06-22 4 S 0 80000 10.5458 D 3180972 D Common Stock 2020-06-22 4 S 0 10432 13.0089 D 3170540 D Common Stock 2020-06-23 4 M 0 29609 1.7554 A 3200149 D Common Stock 2020-06-23 4 S 0 29609 13.0073 D 3170540 D Stock Option (right to buy) 1.7554 2020-06-19 4 M 0 9337 0.00 D 2024-12-18 Common Stock 9337 303994 D Stock Option (right to buy) 1.7554 2020-06-22 4 M 0 136729 0.00 D 2024-12-18 Common Stock 136729 167265 D Stock Option (right to buy) 1.7554 2020-06-23 4 M 0 29609 0.00 D 2024-12-18 Common Stock 29609 137656 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 December 12, 2019. Represents the weighted average share price of an aggregate total of 13,737 shares sold in the price range of $9.00 to $9.02 by the reporting person. The reporting person undertakes to provide upon request by the Commission staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price. Represents the weighted average share price of an aggregate total of 66,263 shares sold in the price range of $9.25 to $9.71 by the reporting person. The reporting person undertakes to provide upon request by the Commission staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price. Represents the weighted average share price of an aggregate total of 80,000 shares sold in the price range of $10.50 to $10.88 by the reporting person. The reporting person undertakes to provide upon request by the Commission staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price. Represents the weighted average share price of an aggregate total of 10,432 shares sold in the price range of $13.00 to $13.10 by the reporting person. The reporting person undertakes to provide upon request by the Commission staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price. Represents the weighted average share price of an aggregate total of 29,609 shares sold in the price range of $13.00 to $13.04 by the reporting person. The reporting person undertakes to provide upon request by the Commission staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price. Subject to the reporting person's continuing service, one twenty-fourth (1/24th) of the shares subject to the option shall vest each month on the same day as the vesting commencement date, such that the shares subject to the option shall become fully vested and exercisable on the second (2nd) anniversary of the vesting commencement date. The vesting commencement date for this option is December 18, 2014. The option originally covered 200,000 pre 1.8515 for 1 forward split shares. Pursuant to the reporting person's employment agreement, the shares subject to the option shall be subject to certain accelerated vesting and post-termination exercise period provisions upon certain events. President and Chief Administrative Officer /s/ Sonja Nelson, as Attorney-in-Fact 2020-06-23