Alector Inc

Item 5. Other Information

(a) None.

(b) None.

(c) During our last fiscal quarter, the following officers and directors adopted or terminated a “Rule 10b5-1 trading arrangement” as defined in Regulation S-K Item 408, as follows:

On September 12, 2024, Marc Grasso, the Company’s Chief Financial Officer, terminated a Rule 10b5-1 trading plan that was originally adopted on August 28, 2023 and provided for (i) the exercise of vested stock options to purchase an aggregate of up to 75,501 shares of the Company’s common stock, and (ii) the sale from time to time of an aggregate of up to 89,362 shares of the Company’s common stock. The terminated plan would have expired on September 30, 2024 had it not been terminated.

On September 13, 2024, Dr. Grasso adopted a Rule 10b5-1 trading plan. Dr. Grasso’s plan provides for (i) the exercise of vested stock options to purchase an aggregate of up to 75,501 shares of the Company's common stock, and (ii) the sale from time to time of an aggregate of up to 84,357 shares of the Company’s common stock. Sales of the shares of the Company’s common stock set forth in Dr. Grasso's trading plan, if any, will be made at or above specified market prices. The trading plan will expire on September 13, 2025, or earlier if all transactions under the trading plan are completed. Dr. Grasso’s trading plan was entered into during an open insider trading window and is intended to satisfy the affirmative defense in Rule 10b5-1(c) under the Exchange Act and the Company’s policies regarding insider transactions.

Other than as disclosed above, during our last fiscal quarter, no other officer or director (as defined in Rule 16a-1(f) under the Exchange Act)adopted orterminated a “Rule 10b5-1 trading arrangement” or a "non-Rule 10b5-1 trading arrangement" (each as defined in Item 408 of Regulation S-K).