X0306 4 2021-01-27 0 0001478320 Adaptive Biotechnologies Corp ADPT 0001780773 BALDO LANCE C/O ADAPTIVE BIOTECHNOLOGIES CORP. SUITE 200 SEATTLE WA 98102 0 1 0 0 Chief Medical Officer Common Stock 2021-01-27 4 M 0 40000 7.80 A 40000 D Common Stock 2021-01-27 4 S 0 17499 58.22 D 22501 D Common Stock 2021-01-27 4 S 0 14233 59.24 D 8268 D Common Stock 2021-01-27 4 S 0 8268 60.01 D 0 D Stock Option (Right to Buy) 7.80 2021-01-27 4 M 0 40000 0.00 D 2029-05-06 Common Stock 40000 341250 D The transactions reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 1, 2020. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $57.69 to 58.655, inclusive. The reporting person undertakes to provide to Adaptive Biotechnologies Corporation, any security holder of Adaptive Biotechnologies Corporation, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in any footnotes to this Form 4. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $58.715 to 59.60, inclusive. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $59.715 to 60.43, inclusive. The options vested with respect to 1/4 of the shares on May 6, 2020, with 1/48 of the shares vesting thereafter at the end of each full month of continuous service until fully vested. /s/ Lance Baldo by Eric L. Billings, attorney-in-fact 2020-01-29