X0306 4 2022-01-11 0 0001827087 Vigil Neuroscience, Inc. VIGL 0001451612 Booth Bruce VIGIL NEUROSCIENCE, INC. 1 BROADWAY, 7TH FLOOR, SUITE 07-300 CAMBRIDGE MA 02142 1 0 0 0 Common Stock 2022-01-11 4 C 0 2831520 A 4273896 I By Atlas Venture Fund XII, L.P. Common Stock 2022-01-11 4 C 0 1027978 A 1027978 I By Atlas Venture Opportunity Fund I, L.P. Common Stock 2022-01-11 4 P 0 535000 14.00 A 4808896 I By Atlas Venture Fund XII, L.P. Series A Preferred Stock 2022-01-11 4 C 0 7852374 0.00 D Common Stock 2831520 0 I By Atlas Venture Fund XII, L.P. Series B Preferred Stock 2022-01-11 4 C 0 2850789 0.00 D Common Stock 1027978 0 I By Atlas Venture Opportunity Fund I, L.P. 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. 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. The Reporting Person is a member of AVA XII LLC and disclaims beneficial ownership of such securities held by Atlas Venture Fund XII, except to the extent of his pecuniary interest therein, if any. The 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. The Reporting Person is a member of AVAO I LLC and disclaims beneficial ownership of such securities held by Atlas Venture Opportunity Fund I, except to the extent of his pecuniary interest therein, if any. 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. /s/ Ommer Chohan, Attorney-in-Fact 2022-01-11