Alector CEO gifts 2.1M shares to family trusts

Q: What insider transactions did ALEC CEO Arnon Rosenthal report on August 19, 2026?

Arnon Rosenthal reported four bona fide gift transactions in Alector common stock involving family trusts on August 19, 2026, plus an updated direct-holdings entry. The activity reflects reallocations among trusts for which he serves as trustee.

Q: How many Alector (ALEC) shares were transferred in total in this Form 4?

The filing reports 2,100,000 Alector common shares involved in bona fide gift transactions: 1,050,000 shares disposed from The Rosenthal Family Revocable Trust and 350,000 shares acquired by each of three separate 2007 family trusts.

Q: Were the Alector (ALEC) insider transactions made under a Rule 10b5-1 trading plan?

The filing indicates the Rule 10b5-1 checkbox is not marked as affirmative, and the footnotes do not describe a trading plan. The transactions are characterized as bona fide gifts involving family trusts.

Q: Which entities hold the Alector (ALEC) shares referenced in the footnotes?

The filing states that shares are held directly by The Rosenthal Family Revocable Trust and by three separate trusts: the Adi Rosenthal 2007 Trust, the Noam Rosenthal 2007 Trust, and the Shani Rosenthal 2007 Trust, with Arnon Rosenthal serving as trustee for each.

Alector, Inc. (ALEC) director and Chief Executive Officer Arnon Rosenthal reported a series of bona fide gift transfers of Alector common stock among family trusts on August 19, 2026.

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Filing Sentiment

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Form Type

Rhea-AI Filing Summary

Alector, Inc. (ALEC) director and Chief Executive Officer Arnon Rosenthal reported a series of bona fide gift transfers of Alector common stock among family trusts on August 19, 2026. An indirect holding of 1,050,000 shares held by The Rosenthal Family Revocable Trust was gifted, while three separate family trusts each received 350,000 shares, all with a reported price of $0.0000 per share. After these transactions, Rosenthal reported 2,367,206 shares held directly, with the referenced trusts holding additional shares indirectly for which he serves as trustee.

Insider Trade Summary

2,100,000 shares gifted

Gift 5 txns

Insider Rosenthal Arnon

Role Chief Executive Officer

Type	Security	Shares	Price	Value
Gift	Common Stock ^F1	1,050,000	$0.00	$0.00
Gift	Common Stock ^F2	350,000	$0.00	$0.00
Gift	Common Stock ^F3	350,000	$0.00	$0.00
Gift	Common Stock ^F4	350,000	$0.00	$0.00
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 1,002,500 shares (Indirect, See footnote); Common Stock — 2,367,206 shares (Direct)

Footnotes (4)

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.
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.
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.
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.

Key Figures

Shares gifted from Rosenthal Family Revocable Trust: 1,050,000 shares Shares received by each 2007 family trust: 350,000 shares Total shares involved in bona fide gift transactions: 2,100,000 shares +2 more

5 metrics

Shares gifted from Rosenthal Family Revocable Trust 1,050,000 shares Bona fide gift disposition on August 19, 2026 by trust for which the Reporting Person serves as trustee

Shares received by each 2007 family trust 350,000 shares Bona fide gift acquisitions on August 19, 2026 by each of Adi, Noam, and Shani Rosenthal 2007 Trusts

Total shares involved in bona fide gift transactions 2,100,000 shares Aggregate giftShares reported in transactionSummary

Direct holdings after transactions 2,367,206 shares Total shares of Alector common stock held directly by Arnon Rosenthal following the reported transactions

Reported transaction price per share $0.0000 per share Price field for each bona fide gift of Alector common stock

Key Terms

bona fide gift, indirect, reporting person, trustee

4 terms

bona fide gift regulatory

"transaction_code_description: Bona fide gift"

A bona fide gift is a genuine, voluntary transfer of money, property, or benefits from one party to another made without expectation of repayment, services, or hidden conditions. Investors care because such gifts can affect company disclosures, related‑party transaction rules, tax treatment, and perceived conflicts of interest; think of it like someone giving you a present with no strings attached — but on a corporate scale, auditors and regulators need to verify it really is unconditional.

indirect financial

"ownership_type: indirect"

reporting person regulatory

"for which the Reporting Person serves as trustee"

trustee financial

"for which the Reporting Person serves as trustee"

A trustee is a person or institution legally appointed to hold and manage assets or enforce an agreement on behalf of other people (beneficiaries). Think of a trustee as a neutral referee or custodian who must act in the beneficiaries’ best interests, follow the trust or contract rules, and handle distributions, recordkeeping and enforcement. Investors care because a trustworthy trustee protects their rights, ensures promised payments or remedies are delivered, and can influence recoveries if things go wrong.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transactions did ALEC CEO Arnon Rosenthal report on August 19, 2026?

Arnon Rosenthal reported four bona fide gift transactions in Alector common stock involving family trusts on August 19, 2026, plus an updated direct-holdings entry. The activity reflects reallocations among trusts for which he serves as trustee.

How many Alector (ALEC) shares were transferred in total in this Form 4?

The filing reports 2,100,000 Alector common shares involved in bona fide gift transactions: 1,050,000 shares disposed from The Rosenthal Family Revocable Trust and 350,000 shares acquired by each of three separate 2007 family trusts.

What are Arnon Rosenthal’s reported direct Alector (ALEC) holdings after these transactions?

Following the reported transactions, Arnon Rosenthal’s direct holdings are listed as 2,367,206 shares of Alector common stock. Additional shares are held indirectly through family trusts for which he acts as trustee.

Were the Alector (ALEC) insider transactions made under a Rule 10b5-1 trading plan?

The filing indicates the Rule 10b5-1 checkbox is not marked as affirmative, and the footnotes do not describe a trading plan. The transactions are characterized as bona fide gifts involving family trusts.

Which entities hold the Alector (ALEC) shares referenced in the footnotes?

The filing states that shares are held directly by The Rosenthal Family Revocable Trust and by three separate trusts: the Adi Rosenthal 2007 Trust, the Noam Rosenthal 2007 Trust, and the Shani Rosenthal 2007 Trust, with Arnon Rosenthal serving as trustee for each.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 08/21/2026 - 06:00 PM EDT Accepted by SEC EDGAR 08/21/2026 - 06:00 PM EDT

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).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Rosenthal Arnon

(Last)

(First)

(Middle)

C/O ALECTOR, INC.

131 OYSTER POINT BLVD., SUITE 600

(Street)

SOUTH SAN FRANCISCO

CALIFORNIA

94080

(City)

(State)

(Zip)

UNITED STATES

(Country)

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
X	Officer (give title below)	Other (specify below)
	Chief Executive Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/19/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	08/19/2026		G		1,050,000	D	$0	922,875	I	See footnote⁽¹⁾
Common Stock	08/19/2026		G		350,000	A	$0	1,002,500	I	See footnote⁽²⁾
Common Stock	08/19/2026		G		350,000	A	$0	1,002,500	I	See footnote⁽³⁾
Common Stock	08/19/2026		G		350,000	A	$0	1,002,500	I	See footnote⁽⁴⁾
Common Stock								2,367,206	D

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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:

1. 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.

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

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

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

	/s/ Grace Wong-Sarad, by power of attorney	08/21/2026
	** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

Source: View Original Filing on SEC EDGAR