SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF 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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1. Name and Address of Reporting Person* Rosenthal Arnon (Last) (First) (Middle) C/O ALECTOR, INC. 151 OYSTER POINT BLVD., SUITE 300 (Street) SOUTH SAN FRANCISCO CA 94080 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 02/06/2019	3. Issuer Name and Ticker or Trading Symbol Alector, Inc. [ ALEC ]
		4. 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	5. If Amendment, Date of 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

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	1,305,226	D
Common Stock	2,612,500	I	See footnote(1)
Common Stock	712,500	I	See footnote(2)
Common Stock	712,500	I	See footnote(3)
Common Stock	712,500	I	See footnote(4)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (right to buy)	(5)	07/01/2028	Common Stock	500,000	$8.16	D
Stock Option (right to buy)	(6)	11/05/2028	Common Stock	275,000	$10.14	D

Explanation of Responses:

1. 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.

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

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

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

5. One forty-eighth (1/48th) of the shares subject to the option vested on August 2, 2018, and an additional one forty-eighth (1/48th) of the shares subject to the option shall vest each month thereafter.

6. One fourth (1/4th) of the shares subject to the option shall vest on November 1, 2019, and one forty-eighth (1/48th) of the shares subject to the option shall vest each month thereafter.

Remarks:

	/s/ Stephanie Yonker, attorney-in-fact	02/06/2019
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (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).
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