Alector, Inc. — Director's Dealing 2023

Sep 13, 2023

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Alector, Inc. (ALEC)
CIK: 0001653087
Period of Report: 2023-09-11

Reporting Person: Polaris Venture Management Co. VI, L.L.C. (10% Owner)
Reporting Person: Polaris Venture Partners VI (AIV), L.P. (10% Owner)
Reporting Person: Polaris Venture Partners Founders' Fund VI, L.P. (10% Owner)
Reporting Person: Polaris Venture Partners VI, L.P. (10% Owner)
Reporting Person: Polaris Venture Partners VI (AIV-B), L.P. (10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2023-09-11	Common Stock	S	500000	$6.00	Disposed	10853817	Indirect

Footnotes

F1: 27,606 shares were sold by Polaris Venture Partners Founders' Fund VI, L.P. ("PVPFF VI"), 379,180 shares were sold by Polaris Venture Partners VI (AIV), L.P. ("PVP VI AIV") and 93,214 shares were sold by Polaris Venture Partners VI (AIV-B), L.P. (p/k/a PVP VI (AIV) Feeder Corp. Holding Partnership, L.P., "PVP VI AIV-B" and, together with PVPFF VI, PVP VI AIV and Polaris Venture Partners VI, L.P. ("PVP VI"), the "Polaris Funds").

F2: (Continued from footnote 1) The general partner of each of the Polaris Funds is Polaris Venture Management Co. VI, L.L.C. ("PVM"). Each of Amir Nashat, Brian Chee, David Barrett, Bryce Youngren, Jonathan Flint, and Terrance McGuire, a member of the Issuer's board of directors, are managing members of PVM (collectively, the "Managing Members") and may be deemed to have shared power to vote and dispose of the shares held by the Polaris Funds. Each of the Managing Members and PVM disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interest therein.

F3: 599,251 shares are held by PVPFF VI, 7,831,004 shares are held by PVP VI AIV, 1,925,094 shares are held by PVP VI AIV-B and 498,468 shares are held by PVP VI. Each of the Managing Members and PVM disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interest therein.