X0609 4 2026-06-17 0001653087 Alector, Inc. ALEC 0001214133 SCHELLER RICHARD H false C/O ALECTOR, INC. 131 OYSTER POINT BLVD., SUITE 600 SOUTH SAN FRANCISCO CA 94080 true false false false false Common Stock 2026-06-17 4 A false 28700 0.00 A 134899 D Stock Option (right to buy) 0 2026-06-17 4 A false 9450 0 A 2036-06-16 Common Stock 9450 9450 D The reported shares are represented by restricted stock units, or RSUs, which vest on the earlier of (i) June 17, 2027 or (ii) the date of the Issuer's next annual meeting of stockholders. The shares subject to the option vest in 12 equal monthly installments beginning on July 17, 2026, provided that the shares subject to the option will vest in full on the earlier of the one-year anniversary of the date of grant or the date of the Issuer's next annual meeting of stockholders. /s/ Grace Wong-Sarad, by power of attorney 2026-06-17