SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* MCGUIRE TERRANCE (Last) (First) (Middle) C/O POLARIS VENTURE PARTNERS LP ONE MARINA PARK DRIVE, 10TH FLOOR (Street) BOSTON MA 02210 (City) (State) (Zip)	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 Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 02/11/2019
	4. 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 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	02/11/2019		C		500,000	A	(1)	500,000	I	See footnote(2)
Common Stock	02/11/2019		C		5,274,725	A	(1)	5,774,725	I	See footnotes(2)(3)
Common Stock	02/11/2019		C		2,500,000	A	(1)	8,274,725	I	See footnotes(2)(3)(4)
Common Stock	02/11/2019		C		2,808,989	A	(1)	11,083,714	I	See footnotes(2)(3)(4)(5)
Common Stock	02/11/2019		C		1,246,883	A	(1)	12,330,597	I	See footnotes(2)(3)(4)(5)(6)
Common Stock	02/11/2019		C		527,597	A	(1)	12,858,194	I	See footnotes(2)(3)(4)(5)(6)(7)

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 Securities Underlying Derivative Security (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: 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
Series A-1 Preferred Stock	(1)	02/11/2019		C			500,000	(1)	(1)	Common Stock	500,000	$0.00	0	I	See footnote(2)
Series A-2 Preferred Stock	(1)	02/11/2019		C			5,274,725	(1)	(1)	Common Stock	5,274,725	$0.00	0	I	See footnote(3)
Series B Preferred Stock	(1)	02/11/2019		C			2,500,000	(1)	(1)	Common Stock	2,500,000	$0.00	0	I	See footnote(4)
Series C Preferred Stock	(1)	02/11/2019		C			2,808,989	(1)	(1)	Common Stock	2,808,989	$0.00	0	I	See footnote(5)
Series D Preferred Stock	(1)	02/11/2019		C			1,246,883	(1)	(1)	Common Stock	1,246,883	$0.00	0	I	See footnote(6)
Series E Preferred Stock	(1)	02/11/2019		C			527,597	(1)	(1)	Common Stock	527,597	$0.00	0	I	See footnote(7)

Explanation of Responses:

1. All of the reported securities are held directly by the Polaris Funds (as defined below). Each of the Series A-1 Preferred Stock, Series A-2 Preferred Stock, Series B Preferred Stock, Series C Preferred Stock, Series D Preferred Stock and Series E Preferred Stock converted into Common Stock on a one-for-one basis upon the closing of the Issuer's initial public offering without payment of further consideration. The shares have no expiration date.

2. 27,606 shares are held by Polaris Venture Partners Founders' Fund VI, L.P ("PVPFF VI"), 379,174 shares are held by Polaris Venture Partners VI (AIV), L.P. ("PVP VI AIV") and 93,220 shares are held by PVP VI (AIV) Feeder Corp. Holding Partnership, L.P. ("PVP VI Feeder" and, together with PVP VI AIV, PVPFF VI, and Polaris Venture Partners VI, L.P. ("PVP VI"), the "Polaris Funds"). The general partner of each of the Polaris Funds is Polaris Venture Management Co. VI, L.L.C. ("PVM"). PVM may be deemed to have sole power to vote and dispose of the shares held by the Polaris Funds. Amir Nashat, Brian Chee, David Barrett, Bryce Youngren, Jon Flint, and the reporting person are managing members of PVM. The reporting person disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that the reporting person is the beneficial owner of such securities, except to the extent of his pecuniary interest therein, if any.

3. 291,223 shares are held by PVPFF VI, 4,000,075 shares are held by PVP VI AIV and 983,427 shares are held by PVP VI Feeder. The reporting person disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that the reporting person is the beneficial owner of such securities, except to the extent of his pecuniary interest therein, if any.

4. 138,030 shares are held by PVPFF VI, 1,895,867 shares are held by PVP VI AIV and 466,103 shares are held by PVP VI Feeder. The reporting person disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that the reporting person is the beneficial owner of such securities, except to the extent of his pecuniary interest therein, if any.

5. 155,087 shares are held by PVPFF VI, 2,130,190 shares are held by PVP VI AIV and 523,712 shares are held by PVP VI Feeder. The reporting person disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that the reporting person is the beneficial owner of such securities, except to the extent of his pecuniary interest therein, if any.

6. 68,842 shares are held by PVPFF VI, 945,571 shares are held by PVP VI AIV and 232,470 shares are held by PVP VI Feeder. The reporting person disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that the reporting person is the beneficial owner of such securities, except to the extent of his pecuniary interest therein, if any.

7. 29,129 shares are held by PVPFF VI and 498,468 shares are held by PVP VI. The reporting person disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that the reporting person is the beneficial owner of such securities, except to the extent of his pecuniary interest therein, if any.

Remarks:

	/s/ Terrance McGuire	02/13/2019
	** 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 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).
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