ROBINS HARLAN S 4

What Happened
Harlan S. Robins, Chief Scientific Officer of Adaptive Biotechnologies (ADPT), sold a total of 42,788 shares in two open-market transactions on Feb 2–3, 2026, for aggregate proceeds of about $799,105. The larger block was 34,668 shares reported at a weighted average price of $18.60 (proceeds $644,825) and the second was 8,120 shares at a weighted average price of $19.00 (proceeds $154,280). These were sales (not purchases), which are often routine disposition of holdings.

Key Details

• Transaction dates and reported prices:
  • 2026-02-02: 34,668 shares sold, weighted avg $18.60 (prices ranged $18.26–$18.88) — $644,825 proceeds (F2).
  • 2026-02-03: 8,120 shares sold, weighted avg $19.00 (prices ranged $18.56–$19.38) — $154,280 proceeds (F3).
• Total: 42,788 shares sold for approximately $799,105.
• Reported under transaction code S (Sale).
• These sales were executed pursuant to a Rule 10b5-1 trading plan adopted Aug 11, 2025 (F1).
• The filing (Form 4) was dated Feb 4, 2026 for trades on Feb 2–3, 2026 — appears to be timely (Form 4 is generally due within two business days).
• Shares owned after the transaction: not disclosed in the provided filing.

Context
A 10b5-1 plan indicates the trades were pre-planned and may be routine, so they do not necessarily reflect the insider’s current view of the company. For retail investors, purchases typically carry more informational weight than routine sales; this filing documents a scheduled sale under an established plan. The footnotes note weighted-average pricing and offer to provide per-trade price breakouts on request.