Alector amends bylaws, elects directors, ratifies auditor at 2023 annual meeting

On June 10, 2023, the Board of Directors (the “Board”) of Alector, Inc. (“Alector”) approved Alector’s Amended and Restated Bylaws (the “Bylaws”) effective as of June 15, 2023. The Bylaws were amended and restated to, among other things: • enhance procedural mechanics and disclosure requirements in connection with stockholder nominations of directors and submissions of proposals regarding other business at Alector’s annual meeting of stockholders (except for proposals properly made in accordance with Rule 14a-8 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”)), including by requiring additional background information and disclosures regarding proposing stockholders, proposed nominees and business, and other persons related to a stockholder’s solicitation of proxies; • change certain provisions relating to stockholder nominees for election as a director to address the new “universal proxy rules” in accordance with Rule 14a-19 under the Exchange Act; • revise ce

1. The Class II director nominees were elected to serve until Alector’s 2026 annual meeting of stockholders and until their successors are elected and qualified. The voting results were as follows: Director Name Votes For Votes Withheld Broker Non-Vote Elizabeth Garofalo, M.D. 60,676,396 918,292 11,001,084 Terry McGuire 54,251,697 7,342,991 11,001,084 Kristine Yaffe, M.D. 54,111,053 7,483,635 11,001,084

2. Stockholders ratified the appointment of Ernst & Young LLP as Alector’s independent registered accounting firm for the fiscal year ending December 31, 2023. The voting results were as follows: Votes For Votes Against Abstentions Broker Non-Vote 72,466,471 64,571 64,730 0

3. Stockholders approved, on a non-binding advisory basis, the compensation of Alector’s named executive officers as disclosed in the proxy statement for the Annual Meeting, known as the Say-on-Pay vote. The voting results were as follows: Votes For Votes Against Abstentions Broker Non-Vote 58,053,865 3,397,559 143,263 11,001,085