Officer Sells Stock Under Rule 10b5-1 Plan

Susan Bobulsky, Chief Commercial Officer, MRD of Adaptive Biotechnologies Corp (ADPT), sold 5,000 shares of common stock on June 11, 2026, at a price of $19.00 per share. This transaction was executed as part of a pre-arranged Rule 10b5-1 trading plan adopted on December 16, 2025. Following the sale, Ms. Bobulsky directly owns 411,775 shares of common stock. The filing is a Form 4, indicating a change in beneficial ownership.