X0306 4 2021-01-04 0 0001478320 Adaptive Biotechnologies Corp ADPT 0001202785 DOBMEIER ERIC C/O ADAPTIVE BIOTECHNOLOGIES CORP. SUITE 200 SEATTLE WA 98102 1 0 0 0 Common Stock 2021-01-04 4 M 0 10000 6.32 A 10000 D Common Stock 2021-01-04 4 S 0 3283 56.10 D 6717 D Common Stock 2021-01-04 4 S 0 5725 57.76 D 992 D Common Stock 2021-01-04 4 S 0 592 58.67 D 400 D Common Stock 2021-01-04 4 S 0 400 59.46 D 0 D Stock Option (Right to Buy) 6.32 2021-01-04 4 M 0 10000 0.00 D 2026-10-18 Common Stock 10000 35000 D The transactions reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on June 3, 2020. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $55.67 to 56.61, 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 $57.27 to 58.18, inclusive. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $58.395 to 59.27, inclusive. The options vested with respect to 1/4 of the reporting person's shares on September 28, 2017, with an additional 1/48 of such shares vesting thereafter at the end of each full month of continuous service until fully vested. /s/ Eric Dobmeier by Eric Billings, Attorney-in-Fact 2021-01-06