Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * Rosenthal Arnon 2. Issuer Name and Ticker or Trading Symbol Alector, Inc. [ALEC] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Chief Executive Officer (Last) (First) (Middle) C/O ALECTOR, INC., 131 OYSTER POINT BLVD, SUITE 600 3. Date of Earliest Transaction (Month/Day/Year) 11/10/2025 (Street) SOUTH SAN FRANCISCO, CA 94080 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Joint/Group Filing (Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 11/10/2025 A 174,167(1) A $ 0 2,524,387 D Common Stock 1,972,875 I See footnote(2) Common Stock 652,500 I See footnote(3) Common Stock 652,500 I See footnote(4) Common Stock 652,500 I See footnote(5)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Employee Stock Option (right to buy)

$1.31

11/10/2025

A

522,500

(6)

11/09/2035

Common Stock

522,500

$ 0

522,500

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Rosenthal Arnon C/O ALECTOR, INC. 131 OYSTER POINT BLVD, SUITE 600 SOUTH SAN FRANCISCO, CA 94080	X		Chief Executive Officer

Signatures

/s/ Grace Wong-Sarad, by power of attorney		11/12/2025
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	The reported shares are represented by restricted stock units, or RSUs, which vest in 12 equal quarterly installments beginning on December 1, 2025.
(2)	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.
(3)	The reported securities are held directly by the Adi Rosenthal 2007 Trust dated March 27, 2007, for which the Reporting Person serves as trustee.
(4)	The reported securities are held directly by the Noam Rosenthal 2007 Trust dated March 27, 2007, for which the Reporting Person serves as trustee.
(5)	The reported securities are held directly by the Shani Rosenthal 2007 Trust dated March 27, 2007, for which the Reporting Person serves as trustee.
(6)	Shares subject to the option vest in 48 equal monthly installments beginning on December 10, 2025.

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