Sec Form 4 Filing - Atlas Venture Fund XII, L.P. @ Vigil Neuroscience, Inc. - 2022-01-11

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Atlas Venture Fund XII, L.P. 2. Issuer Name and Ticker or Trading Symbol Vigil Neuroscience, Inc. [ VIGL] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 300 TECHNOLOGY SQUARE, 8TH FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 01/11/2022 (Street) CAMBRIDGE, MA02139 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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) Code V Amount (A) or (D) Price Common Stock 01/11/2022 C 2,831,520 A 4,273,896 I By Atlas Venture Fund XII, L.P.( 2 ) Common Stock 01/11/2022 C 1,027,978 A 1,027,978 I By Atlas Venture Opportunity Fund I, L.P.( 3 ) Common Stock 01/11/2022 P 535,000 A $ 14( 4 ) 4,808,896 I By Atlas Venture Fund XII, L.P.( 2 )

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Series A Preferred Stock ( 1 ) 01/11/2022 C 7,852,374 ( 1 ) ( 1 ) Common Stock 2,831,520 $ 0 0 I By Atlas Venture Fund XII, L.P.( 2 ) Series B Preferred Stock ( 1 ) 01/11/2022 C 2,850,789 ( 1 ) ( 1 ) Common Stock 1,027,978 $ 0 0 I By Atlas Venture Opportunity Fund I, L.P.( 3 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Atlas Venture Fund XII, L.P. 300 TECHNOLOGY SQUARE, 8TH FLOOR CAMBRIDGE, MA02139 X Atlas Venture Associates XII, L.P. 300 TECHNOLOGY SQUARE, 8TH FLOOR CAMBRIDGE, MA02139 X Atlas Venture Associates XII, LLC 300 TECHNOLOGY SQUARE, 8TH FLOOR CAMBRIDGE, MA02139 X Atlas Venture Opportunity Fund I, L.P. 300 TECHNOLOGY SQUARE, 8TH FLOOR CAMBRIDGE, MA02139 X Atlas Venture Associates Opportunity I, L.P. 300 TECHNOLOGY SQUARE, 8TH FLOOR CAMBRIDGE, MA02139 X Atlas Venture Associates Opportunity I, LLC 300 TECHNOLOGY SQUARE, 8TH FLOOR CAMBRIDGE, MA02139 X Signatures Atlas Venture Fund XII, L.P. By: Atlas Venture Associates XII, L.P., Its: General Partner By: Atlas Venture Associates XII, LLC, Its General Partner, By: /s/ Ommer Chohan 01/11/2022 Signature of Reporting Person Date Atlas Venture Associates XII, L.P., By: Atlas Venture Associates XII, LLC, Its General Partner, By: /s/ Ommer Chohan 01/11/2022 Signature of Reporting Person Date Atlas Venture Associates XII, LLC, By: /s/ Ommer Chohan 01/11/2022 Signature of Reporting Person Date Atlas Venture Opportunity Fund I, L.P., By: Atlas Venture Associates Opportunity I, L.P., its general partner, By: Atlas Venture Associates Opportunity I, LLC, its general partner, By: Ommer Chohan, Chief Financial Officer /s/ Ommer Chohan 01/11/2022 Signature of Reporting Person Date Atlas Venture Associates Opportunity I, L.P., By: Atlas Venture Associates Opportunity I, LLC, its general partner, By: Ommer Chohan, Chief Financial Officer /s/ Ommer Chohan 01/11/2022 Signature of Reporting Person Date Atlas Venture Associates Opportunity I, LLC By: Ommer Chohan, Chief Financial Officer /s/ Ommer Chohan 01/11/2022 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Each share of Series A Preferred Stock and Series B Preferred Stock automatically converted into shares of the Issuer's common stock, par value $0.0001 per share ("Common Stock") on a one-for-2.7732 basis upon the closing of the Issuer's initial public offering on January 11, 2022 and had no expiration date. ( 2 )These shares are held directly by Atlas Venture Fund XII, L.P. ("Atlas Venture Fund XII"). The general partner of Atlas Venture Fund XII is Atlas Venture Associates XII, L.P. ("AVA XII LP"). Atlas Venture Associates XII, LLC ("AVA XII LLC") is the general partner of AVA XII LP. Each of AVA XII LP and AVA XII LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund XII, except to the extent of its pecuniary interest therein, if any. ( 3 )These shares are held directly by Atlas Venture Opportunity Fund I, L.P. ("Atlas Venture Opportunity Fund I"). The general partner of Atlas Venture Opportunity Fund I is Atlas Venture Associates Opportunity I, L.P. ("AVAO I LP"). Atlas Venture Associates Opportunity I, LLC ("AVAO I LLC") is the general partner of AVAO I LP. Each of AVAO I LP and AVAO I LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Opportunity Fund I, except to the extent of its pecuniary interest therein, if any. ( 4 )On January 11, 2022, Atlas Venture Fund XII purchased 535,000 shares of Common Stock of the Issuer at a price of $14.00 per share pursuant to an underwritten public offering.

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