X0306 4 2021-02-14 0 0001478320 Adaptive Biotechnologies Corp ADPT 0001229765 GRIFFIN MICHELLE RENEE C/O ADAPTIVE BIOTECHNOLOGIES CORP. SUITE 200 SEATTLE WA 98102 1 0 0 0 Common Stock 2021-02-14 4 A 0 1504 0.00 A 1504 D Common Stock 2021-02-16 4 M 0 6000 7.80 A 7504 D Common Stock 2021-02-16 4 S 0 6000 65.08 D 1504 D Stock Option (Right to Buy) 66.50 2021-02-14 4 A 0 3759 0.00 A 2031-02-14 Common Stock 3759 3759 D Stock Option (Right to Buy) 7.80 2021-02-16 4 M 0 6000 0.00 D 2029-04-23 Common Stock 6000 89000 D The transactions reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 14, 2020. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $64.49 to 65.45, 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 option will vest in equal monthly installments over one year, subject to continued service as a director through such vesting date. The options vested with respect to 1/4 of such shares on March 28, 2020, with 1/48 of such shares vesting thereafter at the end of each full month of continuous service until fully vested. /s/ Michelle Griffin by Eric Billings, attorney-in-fact 2021-02-17