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* Polaris Venture Management Co. VI, L.L.C. (Last) (First) (Middle) ONE MARINA PARK DRIVE, 10TH FLOOR (Street) BOSTON MA 02210 (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) Director X 10% Owner Officer (give title below) Other (specify below)	5. If Amendment, Date of Original Filed (Month/Day/Year)
			6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X 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)

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
Series A-1 Preferred Stock	(1)	(1)	Common Stock	500,000	(1)	I	See footnote(2)
Series A-2 Preferred Stock	(1)	(1)	Common Stock	5,274,725	(1)	I	See footnote(3)
Series B Preferred Stock	(1)	(1)	Common Stock	2,500,000	(1)	I	See footnote(4)
Series C Preferred Stock	(1)	(1)	Common Stock	2,808,989	(1)	I	See footnote(5)
Series D Preferred Stock	(1)	(1)	Common Stock	1,246,883	(1)	I	See footnote(6)
Series E Preferred Stock	(1)	(1)	Common Stock	527,597	(1)	I	See footnote(7)

1. Name and Address of Reporting Person* Polaris Venture Management Co. VI, L.L.C. (Last) (First) (Middle) ONE MARINA PARK DRIVE, 10TH FLOOR (Street) BOSTON MA 02210 (City) (State) (Zip)

1. Name and Address of Reporting Person* Polaris Venture Partners VI (AIV), L.P. (Last) (First) (Middle) ONE MARINA PARK DRIVE, 10TH FLOOR (Street) BOSTON MA 02210 (City) (State) (Zip)

1. Name and Address of Reporting Person* Polaris Venture Partners Founders' Fund VI, L.P. (Last) (First) (Middle) ONE MARINA PARK DRIVE, 10TH FLOOR (Street) BOSTON MA 02210 (City) (State) (Zip)

1. Name and Address of Reporting Person* PVP VI (AIV) Feeder Corp. Holding Partnership, L.P. (Last) (First) (Middle) ONE MARINA PARK DRIVE, 10TH FLOOR (Street) BOSTON MA 02210 (City) (State) (Zip)

1. Name and Address of Reporting Person* Polaris Venture Partners VI, L.P. (Last) (First) (Middle) ONE MARINA PARK DRIVE, 10TH FLOOR (Street) BOSTON MA 02210 (City) (State) (Zip)

Explanation of Responses:

1. 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 is convertible into Common Stock on a one-for-one basis into the number of shares of Common Stock shown in Column 3 at any time at the holder's election and automatically 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 disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that PVM is the beneficial owner of such securities, except to the extent of its 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. PVM disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that PVM is the beneficial owner of such securities, except to the extent of its 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. PVM disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that PVM is the beneficial owner of such securities, except to the extent of its 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. PVM disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that PVM is the beneficial owner of such securities, except to the extent of its 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. PVM disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that PVM is the beneficial owner of such securities, except to the extent of its pecuniary interest therein, if any.

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

Remarks:

	/s/ Terrance McGuire, Managing Member of Polaris Venture Management Co. VI, L.L.C.	02/06/2019
	/s/ Terrance McGuire, Managing Member of Polaris Venture Management Co. VI, L.L.C., general partner of Polaris Venture Partners VI (AIV), L.P.	02/06/2019
	/s/ Terrance McGuire, Managing Member of Polaris Venture Management Co. VI, L.L.C., general partner of Polaris Venture Partners Founders' Fund VI, L.P.	02/06/2019
	/s/ Terrance McGuire, Managing Member of Polaris Venture Management Co. VI, L.L.C., general partner of PVP VI (AIV) Feeder Corp. Holding Partnership, L.P.	02/06/2019
	/s/ Terrance McGuire, Managing Member of Polaris Venture Management Co. VI, L.L.C., general partner of Polaris Venture Partners VI, L.P.	02/06/2019
	** Signature of Reporting Person	Date
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