Satter Muneer A 4

What Happened
Muneer A. Satter, a director of Annexon, reported a purchase (Code P) of 613,497 shares on May 28, 2026 at $5.41 per share, a transaction valued at approximately $3,319,019. The filing notes the shares were purchased by Alerce Medical Technology Partners, L.P.; the Reporting Person has sole voting and dispositive power over the shares held by Alerce Medical.

Key Details

• Transaction date: May 28, 2026; filing date: May 29, 2026 (timely filing).
• Price and amount: 613,497 shares at $5.41/share; total ≈ $3,319,019.
• Shares controlled after transaction (per filing footnote): includes 240,000 shares in the Muneer A. Satter Revocable Trust; 567,240 in various other trusts/entities; 1,147,738 in Satter Medical Technology Partners, L.P.; and 8,387,156 in Alerce Medical — totals shown in the filing sum to 10,342,134 shares over which he has voting/dispositive power as of May 28, 2026.
• Footnote highlights: (F1) all purchased shares were acquired by Alerce Medical and Satter has sole voting/dispositive power over those shares; (F2) the filing disclaims beneficial ownership of shares held by certain trusts/entities except to the extent of his pecuniary interest.
• Transaction type: Purchase (P) — reported as open-market or private purchase via Alerce Medical.

Context
This was a direct purchase through an affiliated investment vehicle rather than an immediate sale or option exercise. Purchases by insiders or affiliated entities can be interpreted by investors as a positive signal of confidence, but note the filing’s disclaimers regarding beneficial ownership — Satter reports control over the shares but disclaims beneficial ownership of certain holdings except for pecuniary interest.