Form 4 Filing for Alector, Inc. - Errol B. Desouza Transactions

On June 17, 2026, Errol B. Desouza, a director at Alector, Inc., acquired 28,700 shares of Common Stock and was granted a stock option to purchase 9,450 shares of Common Stock. These transactions were reported on Form 4. The acquisition of common stock is represented by restricted stock units (RSUs) that vest on the earlier of June 16, 2027, or the date of the Issuer's next annual meeting. The stock option, with an exercise price of $0.00, vests in 12 equal monthly installments starting July 17, 2026, or earlier upon the one-year anniversary of the grant date or the Issuer's next annual meeting. Following these transactions, Mr. Desouza directly owns 98,650 shares of Common Stock and holds options for 9,450 shares.