X0508 4 2025-03-04 0001478320 Adaptive Biotechnologies Corp ADPT 0001820885 BOBULSKY SUSAN C/O ADAPTIVE BIOTECHNOLOGIES CORPORATION 1165 EASTLAKE AVENUE EAST SEATTLE WA 98109 0 1 0 0 Chief Commercial Officer, MRD 0 Common Stock 2025-03-04 4 A 0 119971 0 A 373261 D Common Stock 2025-03-05 4 S 0 26023 6.98 D 347238 D Stock Option (right to buy) 8.12 2025-03-04 4 A 0 180029 0 A 2035-03-04 Common Stock 180029 180029 D This transaction represents the number of shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of RSUs. This sale is mandated by the Issuer's election under its equity incentive plans to require the satisfaction of tax withholding obligations to be funded by a "sell to cover" transaction and does not represent a discretionary trade by the Reporting Person. The options vest with respect to 1/4 of such shares on March 4, 2026, with 1/48 of such shares vesting thereafter at the end of each full month of continuous service until fully vested. Susan Bobulsky by Kyle Piskel, Attorney-in-Fact 2025-03-06