X0609 4 2026-06-11 0001528115 Annexon, Inc. ANNX 0001553338 Waddill William D. false C/O ANNEXON, INC. 1400 SIERRA POINT PKWY, BLDG C, STE 200 BRISBANE CA 94005 true false false false 0 Stock Option (Right to Buy) 4.70 2026-06-11 4 A 0 65000 0 A 2036-06-11 Common Stock 65000 65000 D The underlying shares subject to the option vest and become exercisable as to 100% of the total number of shares subject to the option on the earlier of (i) the first anniversary of June 11, 2026 or (ii) the next Annual Meeting following June 11, 2026, subject to Reporting Person's continuous service as a director until such vesting date. /s/ Jennifer Lew, Attorney-in-Fact 2026-06-15