Annexon Director Muneer Satter Acquires 613,497 Shares at $5.41

This Form 4 filing discloses that Muneer A. Satter, a director of Annexon, Inc., acquired 613,497 shares of common stock on May 28, 2026, at a price of $5.41 per share. The shares were purchased by Alerce Medical Technology Partners, L.P., over which Satter has sole voting and dispositive power. Following this transaction, Satter's total holdings in Annexon increased to 10,342,134 shares. The filing includes detailed footnotes explaining the ownership structure, noting that Satter holds shares through various trusts and entities, including the Muneer A. Satter Revocable Trust, Satter Medical Technology Partners, L.P., and Alerce Medical. Satter disclaims beneficial ownership of certain shares except to the extent of his pecuniary interest. The transaction was filed on May 29, 2026, and represents a significant purchase by a company director.