# EDGAR Filing Document

**Accession Number:** 0001653087
**File Stem:** 0001209191-23-020421
**Filing Date:** 2023-3
**Character Count:** 6953
**Document Hash:** 90ab8a48fc2a4fbd74341e2d0f2942f5
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001209191-23-020421.hdr.sgml**: 20230321

**ACCESSION NUMBER**: 0001209191-23-020421

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20230303

**FILED AS OF DATE**: 20230321

**DATE AS OF CHANGE**: 20230321

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Rosenthal Arnon
- **CENTRAL INDEX KEY:** 0001757770

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-38792
- **FILM NUMBER:** 23751073

**MAIL ADDRESS:**
- **STREET 1:** C/O ALECTOR, INC.
- **STREET 2:** 151 OYSTER POINT BLVD., #300
- **CITY:** SOUTH SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94080
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Alector, Inc.
- **CENTRAL INDEX KEY:** 0001653087
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **IRS NUMBER:** 822933343
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 131 OYSTER POINT BLVD., SUITE 600
- **CITY:** SOUTH SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94080
- **BUSINESS PHONE:** 415-231-5660

**MAIL ADDRESS:**
- **STREET 1:** 131 OYSTER POINT BLVD., SUITE 600
- **CITY:** SOUTH SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94080

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Alector LLC
- **DATE OF NAME CHANGE:** 20150915

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[ ] 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**<sup>*</sup><br>Rosenthal Arnon<br><sub>(Last) (First) (Middle)</sub><br>C/O ALECTOR, INC.<br>131 OYSTER POINT BLVD, SUITE 600<br><sub>(Street)</sub><br>SOUTH SAN FRANCISCO, CA 94080<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2023-03-03 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [ ] 10% Owner<br>[X] Officer (give title below) [ ] Other (specify below)<br>_Chief Executive Officer_ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Alector, Inc. [ ALEC ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Stock | 2023-03-03 |  | A |  | 42990<sup>(1)</sup> | A | $0.00 | 1671536 | D |  |
| Common Stock | 2023-03-17 |  | S<sup>(2)</sup> |  | 15186 | D | $6.2181 | 1656350 | D |  |
| Common Stock |  |  |  |  |  |  |  | 1972875 | I | See footnote<sup>(3)</sup> |
| Common Stock |  |  |  |  |  |  |  | 652500 | I | See footnote<sup>(4)</sup> |
| Common Stock |  |  |  |  |  |  |  | 652500 | I | See footnote<sup>(5)</sup> |
| Common Stock |  |  |  |  |  |  |  | 652500 | I | See footnote<sup>(6)</sup> |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

---

### Footnotes:

(1) The reported shares are represented by restricted stock units, or RSUs, all of which were fully vested on the grant date.

(2) The reported shares were sold to satisfy the reporting person's tax obligations in connection with the vesting of RSUs.

(3) 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.

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

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

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

**Signature:** /s/ Marc Grasso, by power of attorney  
**Date:** 2023-03-21

### Remarks:

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.**