Officer/Director Stock Acquisition and Option Grant

Kristine Yaffe, a director at Alector, Inc. (ALEC), acquired 28,700 shares of Common Stock on June 17, 2026. This acquisition was part of a restricted stock unit (RSU) grant that vests on the earlier of June 17, 2027, or the date of the Issuer's next annual meeting. Concurrently, Yaffe was granted a stock option to purchase 9,450 shares of Common Stock at a price of $0.00. This option vests in 12 equal monthly installments beginning July 17, 2026, with full vesting occurring on the earlier of the one-year anniversary of the grant date or the Issuer's next annual meeting. Both transactions are reported as direct holdings.