Alector, Inc. — Director's Dealing 2026

Mar 3, 2026

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Alector, Inc. (ALEC)
CIK: 0001653087
Period of Report: 2026-03-02

Reporting Person: Rosenthal Arnon (N/A)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2026-03-02	Common Stock	S	81864	$2.1233	Disposed	2338176	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	1972875	Indirect
Common Stock	652500	Indirect
Common Stock	652500	Indirect
Common Stock	652500	Indirect

Footnotes

F1: The reported shares were sold to satisfy the reporting person's tax obligations in connection with the vesting of restricted stock units, or RSUs.

F2: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $2.04 to $2.37. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff, the issuer, or any security holder of the issuer upon request.

F3: The reported securities are held directly by The Rosenthal Family Revocable Trust Dated November 4, 1994, as restated on June 9, 1999, for which the Reporting Person serves as trustee.

F4: The reported securities are held directly by the Adi Rosenthal 2007 Trust dated March 27, 2007, for which the Reporting Person serves as trustee.

F5: The reported securities are held directly by the Noam Rosenthal 2007 Trust dated March 27, 2007, for which the Reporting Person serves as trustee.

F6: The reported securities are held directly by the Shani Rosenthal 2007 Trust dated March 27, 2007, for which the Reporting Person serves as trustee.