Alector, Inc. entered into a Sales Agreement with TD Securities (USA) LLC (TD Cowen) on May 7, 2026. The agreement allows for the offer and sale of up to $125,000,000 of common stock through 'at-the-market' (ATM) offerings. The company is not obligated to sell any shares and retains control over the timing, price, and volume of any sales. Proceeds are intended for general corporate purposes, including research, development, manufacturing, working capital, and potential strategic transactions. This agreement replaces a previous sales agreement dated November 7, 2023.