X0508 4 2026-02-18 0001528115 Annexon, Inc. ANNX 0001818525 Yednock Ted C/O ANNEXON, INC 1400 SIERRA POINT PKWY, BLDG C, STE 200 BRISBANE CA 94005 false true false false EVP & CHIEF INNOVATION OFFICER 0 Common Stock 2026-02-18 4 S 0 7857 5.11 D 97227 D The shares were sold to cover tax withholding obligations in connection with the vesting of restricted stock units ("RSUs"). This transaction was executed in multiple trades in prices ranging from $4.925 to $5.17, inclusive. The price reported in Column 4 above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote. /s/ Jennifer Lew, Attorney-in-Fact 2026-02-20