Arnon Rosenthal - 19 Aug 2026 Form 4 Insider Report for Alector, Inc. (ALEC)

Reporting relationship: Chief Executive Officer, Director
Issuer ticker: ALEC
Reported as of: 19 Aug 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 21 Aug 2026, 18:00:04 UTC
Prior SEC filing: 03 Jun 2026
Source filing: View source filing
Reporting owner signature: /s/ Grace Wong-Sarad, by power of attorney

Key filing fact

Arnon Rosenthal filed Form 4 for Alector, Inc. (ALEC) on 21 Aug 2026.

Key facts

This page summarizes Arnon Rosenthal's Form 4 filing for Alector, Inc. (ALEC).
4 reported transactions and 0 derivative rows are listed below.
Accepted by SEC: 21 Aug 2026, 18:00.

Change

Previous filing in this sequence was filed on 03 Jun 2026.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001757770 Primary reporting owner

Rosenthal Arnon

Relationship: Chief Executive Officer, Director
Address: C/O ALECTOR, INC., 131 OYSTER POINT BLVD., SUITE 600, SOUTH SAN FRANCISCO
Signature: /s/ Grace Wong-Sarad, by power of attorney
Signature date: 21 Aug 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

ALEC transaction

Common Stock

Gift

Transaction value
Shares: -1,050,000
Change %: -53%
Price: $0.000000^*
Shares after: 922,875
Date: 19 Aug 2026
Ownership: See footnote
Footnotes: F1

ALEC transaction

Common Stock

Gift

Transaction value
Shares: +350,000
Change %: +54%
Price: $0.000000^*
Shares after: 1,002,500
Date: 19 Aug 2026
Ownership: See footnote
Footnotes: F2

ALEC transaction

Common Stock

Gift

Transaction value
Shares: +350,000
Change %: +54%
Price: $0.000000^*
Shares after: 1,002,500
Date: 19 Aug 2026
Ownership: See footnote
Footnotes: F3

ALEC transaction

Common Stock

Gift

Transaction value
Shares: +350,000
Change %: +54%
Price: $0.000000^*
Shares after: 1,002,500
Date: 19 Aug 2026
Ownership: See footnote
Footnotes: F4

ALEC holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 2,367,206
Date: 19 Aug 2026
Ownership: Direct

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 4 footnotes

Footnote F1

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.

Footnote F2

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

Footnote F3

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

Footnote F4

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