Alector, Inc. — Director's Dealing 2025

Jul 1, 2025

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Alector, Inc. (ALEC)
CIK: 0001653087
Period of Report: 2025-07-01

Reporting Person: Rosenthal Arnon (N/A)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2025-07-01	Common Stock	A	137125	$0.00	Acquired	2551782	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2025-07-01	Employee Stock Option (right to buy)	$1.42	A	45700	Acquired	2035-07-01	Common Stock (45700)	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 are represented by restricted stock units, or RSUs, one half (1/2) of the total shares shall vest on December 1, 2025 and one fourth (1/4th) of the total shares shall vest quarterly thereafter.

F2: 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.

F3: The reported securities are held directly by the Adi Rosenthal 2007 Trust dated March 27, 2007, for which the Reporting Person serves as trustee.

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

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

F6: One third (1/3rd) of the total shares subject to the option shall vest on November 1, 2025, and one twelfth (1/12th) of the total shares subject to the option shall vest in equal monthly installments thereafter, provided that the shares subject to the option will vest in full on July 1, 2026.