Arnon Rosenthal - 22 Sep 2021 Form 4 Insider Report for Alector, Inc. (ALEC)

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	ALEC	Common Stock	Sale	$2,395,298	-94,717	-3.9%	$25.29	2,317,783	22 Sep 2021	See footnote	F1, F2, F3
transaction	ALEC	Common Stock	Sale	$137,890	-5,283	-0.23%	$26.10	2,312,500	22 Sep 2021	See footnote	F1, F3, F4
transaction	ALEC	Common Stock	Sale	$241,567	-9,625	-0.42%	$25.10	2,302,875	23 Sep 2021	See footnote	F1, F3, F5
holding	ALEC	Common Stock						1,455,226	22 Sep 2021	Direct
holding	ALEC	Common Stock						712,500	22 Sep 2021	See footnote
holding	ALEC	Common Stock						712,500	22 Sep 2021	See footnote
holding	ALEC	Common Stock						712,500	22 Sep 2021	See footnote

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Id	Content
F1	The sale reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan.
F2	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $25.00 to $25.98, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (1), (3) and (4) to this Form 4.
F3	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.
F4	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $26.00 to $26.22, inclusive.
F5	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $25.00 to $25.26, inclusive.