PYOTT DAVID E I 4

What Happened
David E. I. Pyott, a director of Alnylam Pharmaceuticals, exercised 3,830 stock options (reported as acquired at $0.00) on June 1, 2026 and sold those 3,830 shares in multiple open‑market transactions the same day for aggregate proceeds of $1,145,852 (~$1.15M). The sales were reported in five lots with prices ranging roughly from $297.31 to $302.65 per share.

Key Details

• Transaction date: 2026-06-01 (Form 4 filed 2026-06-03; appears timely)
• Option exercise: 3,830 shares acquired at $0.00 (transaction code M)
• Open‑market sales (total 3,830 shares, total proceeds ~$1,145,852):
  • 921 shares @ $297.71 = $274,191
  • 1,175 shares @ $298.91 = $351,219
  • 1,222 shares @ $299.87 = $366,441
  • 495 shares @ $300.72 = $148,856
  • 17 shares @ $302.65 = $5,145
• Footnotes of note:
  • Sales were made pursuant to a Rule 10b5‑1 trading plan adopted Nov 12, 2025.
  • The options exercised were due to expire June 3, 2026 and were fully vested as of June 3, 2017.
  • The filing discloses that the shares were purchased by the David E. I. Pyott Trust (he is trustee).
• Shares owned after the transactions: not specified in the provided filing details.

Context
This was an exercise of vested options followed by immediate open‑market sales of the resulting shares (a form of cashless exercise/liquidation). Sales done under a pre‑existing 10b5‑1 plan are considered preplanned and routine; they do not by themselves indicate a change in the director’s view on the company. The filing appears timely (filed within two business days).