# EDGAR Filing Document

**Accession Number:** 0001827087
**File Stem:** 0000950170-25-085595
**Filing Date:** 2025-6
**Character Count:** 13844
**Document Hash:** c90a88c8191ba9c96c12fa36f9ccbb3a
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000950170-25-085595.hdr.sgml**: 20250612

**ACCESSION NUMBER**: 0000950170-25-085595

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D/A

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20250612

**DATE AS OF CHANGE**: 20250612

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Vigil Neuroscience, Inc.
- **CENTRAL INDEX KEY:** 0001827087
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-93233
- **FILM NUMBER:** 251043954

**BUSINESS ADDRESS:**
- **STREET 1:** 100 FORGE ROAD
- **STREET 2:** SUITE 700
- **CITY:** WATERTOWN
- **STATE:** MA
- **ZIP:** 02472
- **BUSINESS PHONE:** 857-254-4445

**MAIL ADDRESS:**
- **STREET 1:** 100 FORGE ROAD
- **STREET 2:** SUITE 700
- **CITY:** WATERTOWN
- **STATE:** MA
- **ZIP:** 02472
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Vida Ventures GP III, L.L.C.
- **CENTRAL INDEX KEY:** 0001855502

**ORGANIZATION NAME:**
- **EIN:** 861852530
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A

**BUSINESS ADDRESS:**
- **STREET 1:** 455 MARKET STREET, SUITE 1420
- **CITY:** SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94105
- **BUSINESS PHONE:** (424) 313-1550

**MAIL ADDRESS:**
- **STREET 1:** 455 MARKET STREET, SUITE 1420
- **CITY:** SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94105

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

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**(Amendment No. 3)**

**Vigil Neuroscience, Inc.**

*(Name of Issuer)*

**Common Stock, $0.0001 par value per share**

*(Title of Class of Securities)*

**92673K108**

*(CUSIP Number)*

**Jean-Philippe Kouakou-Zebouah**<br>Vida Ventures GP III, L.L.C.<br>40 Broad Street, Suite 201<br>Boston MA 02109<br>(857) 254-9500

*(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)*

**06/10/2025**

*(Date of Event Which Requires Filing of this Statement)*

| **CUSIP No.** | **92673K108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Vida Ventures III, L.P.** | Name of reporting person<br>**Vida Ventures III, L.P.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**1631038.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**1631038.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**1631038.00** | Aggregate amount beneficially owned by each reporting person<br>**1631038.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**3.5%** | Percent of class represented by amount in Row (11)<br>**3.5%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

**Comment for Reporting Person:** (1) All shares are held of record by Vida III (as defined in Item 2(a) of the Original Schedule 13D (as defined below)). Vida III GP (as defined in Item 2(a) of the Original Schedule 13D) is the general partner of each of Vida III and Vida III-A (as defined in Item 2(a) of the Original 13D) and may be deemed to have voting, investment, and dispositive power with respect to these securities. Each of the Investment Committee (as defined in the Original Schedule 13D) and the members thereof may be deemed to share voting, investment and dispositive power with respect to these securities.

(2) Based upon 46,671,534 shares of the Issuer's Common Stock outstanding as of April 30, 2025, as set forth in the Issuer's quarterly report on Form 10-Q for the quarter ended March 31, 2025, filed with the Securities and Exchange Commission ("Commission") on May 7, 2025 (the "Form 10-Q").

| **CUSIP No.** | **92673K108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Vida Ventures III-A, L.P.** | Name of reporting person<br>**Vida Ventures III-A, L.P.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**3760.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**3760.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**3760.00** | Aggregate amount beneficially owned by each reporting person<br>**3760.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**0%** | Percent of class represented by amount in Row (11)<br>**0%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

**Comment for Reporting Person:** (1) All shares are held of record by Vida III-A. Vida III GP is the general partner of each of Vida III and Vida III-A and may be deemed to have voting, investment, and dispositive power with respect to these securities. Each of the Investment Committee and the members thereof may be deemed to share voting, investment and dispositive power with respect to these securities.

(2 ) Based upon 46,671,534 shares of the Issuer's Common Stock outstanding as of April 30, 2025, as set forth in the Form 10-Q.

| **CUSIP No.** | **92673K108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Vida Ventures GP III, L.L.C.** | Name of reporting person<br>**Vida Ventures GP III, L.L.C.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**AF** | Source of funds (See Instructions)<br>**AF** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**1634798.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**1634798.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**1634798.00** | Aggregate amount beneficially owned by each reporting person<br>**1634798.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**3.5%** | Percent of class represented by amount in Row (11)<br>**3.5%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**OO** | Type of Reporting Person (See Instructions)<br>**OO** | |

---

**Comment for Reporting Person:** (1) Consists of (i) 1,631,038 shares held by Vida III and (ii) 3,760 shares held by Vida III-A. Vida III GP is the general partner of each of Vida III and Vida III-A and may be deemed to have voting, investment, and dispositive power with respect to these securities. Each of the Investment Committee and the members thereof may be deemed to share voting, investment and dispositive power with respect to these securities.

(2) Based upon 46,671,534 shares of the Issuer's Common Stock outstanding as of April 30, 2025, as set forth in the Form 10-Q. .

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Common Stock, $0.0001 par value per share

**(b) Name of Issuer:**
Vigil Neuroscience, Inc.

**(c) Address of Issuer's Principal Executive Offices:**
100 Forge Road, Suite 700, Watertown, MA, 02472

Explanatory Note: This Amendment No. 3 (this Amendment) amends and supplements the Schedule 13D originally filed by the Reporting Persons with the SEC on February 10, 2023, as amended by that Amendment No. 1 filed with the SEC on October 9, 2024 and that Amendment No. 2 filed with the SEC on June 9, 2025 (collectively, the Original Schedule 13D). Only those items that are hereby reported are amended; all other items reported in the Original Schedule 13D remain unchanged. Information given in response to each item shall be deemed incorporated by reference in all other items, as applicable. Capitalized terms not defines in this Amendment have the meanings ascribed to them in the Original Schedule 13D.

**Item 4. Purpose of Transaction**

The information set forth in Item 4 of the Original Schedule 13D is incorporated herein by reference.

**Item 5. Interest in Securities of the Issuer**

**(a)**
See Items 7-11 of the cover pages of this Amendment No. 2. The information reported on such cover pages is reported as of June 11, 2025.

**(b)**
See Items 7-11 of the cover pages of this Amendment No. 2. The information reported on such cover pages is reported as of June 11, 2025.

**(c)**
On June 9, 2025, Vida III sold 367,930 shares of Common Stock at a weighted average price per share of $7.8809 for aggregate proceeds of $2,899,618.414. On June 9, 2025, Vida III-A sold 848 shares of Common Stock at a weighted average price per share of $7.8809 for aggregate proceeds of $6,684.13. On June 10, 2025, Vida III sold 508,273 shares of Common Stock at a weighted average price per share of $7.8734 for aggregate proceeds of $4,001,839.32. On June 10, 2025, Vida III-A sold 1,172 shares of Common Stock at a weighted average price per share of $7.8734 for aggregate proceeds of $9,224.94. On June 11, 2025, Vida III sold 328,222 shares of Common Stock at a weighted average price per share of $7.8702 for aggregate proceeds of $2,583,241.50. On June 11, 2025, Vida III-A sold 757 shares of Common Stock at a weighted average price per share of $7.8702 for aggregate proceeds of $5,954.67.

**Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.**

The information set forth in Item 6 of the Original Schedule 13D is incorporated herein by reference.

### SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Vida Ventures III, L.P.

**Signature:** By: Vida Ventures GP III, L.L.C., its General Partner /s/ Jean-Philippe Kouakou-Zebouah

**Name/Title:** Managing Member

**Date:** 06/12/2025

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Vida Ventures III-A, L.P.

**Signature:** By: Vida Ventures GP III, L.L.C., its General Partner /s/ Jean-Philippe Kouakou-Zebouah

**Name/Title:** Managing Member

**Date:** 06/12/2025

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Vida Ventures GP III, L.L.C.

**Signature:** /s/ Jean-Philippe Kouakou-Zebouah

**Name/Title:** Managing Member

**Date:** 06/12/2025