Arnon Rosenthal - 01 Jul 2025 Form 4 Insider Report for Alector, Inc. (ALEC)

Role: Chief Executive Officer, Director
Signature: /s/ Grace Wong-Sarad, by power of attorney
Issuer symbol: ALEC
Transactions as of: 01 Jul 2025
Net transactions value: $0
Form type: 4
Filing time: 01 Jul 2025, 17:00:10 UTC
Previous filing: 04 Jun 2025
Next filing: 04 Sep 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Rosenthal Arnon	Chief Executive Officer, Director	C/O ALECTOR, INC., 131 OYSTER POINT BLVD., SUITE 600, SOUTH SAN FRANCISCO	/s/ Grace Wong-Sarad, by power of attorney	01 Jul 2025	0001757770

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	ALEC	Common Stock	Award	$0	+137,125	+5.7%	$0.000000	2,551,782	01 Jul 2025	Direct	F1
holding	ALEC	Common Stock						1,972,875	01 Jul 2025	See footnote	F2
holding	ALEC	Common Stock						652,500	01 Jul 2025	See footnote	F3
holding	ALEC	Common Stock						652,500	01 Jul 2025	See footnote	F4
holding	ALEC	Common Stock						652,500	01 Jul 2025	See footnote	F5

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	ALEC	Employee Stock Option (right to buy)	Award	$0	+45,700		$0.000000	45,700	01 Jul 2025	Common Stock	45,700	$1.42	Direct	F6

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
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.