144 0001856597 XXXXXXXX LIVE 0001496963 Squarespace, Inc. 001-40393 225 Varick Street 12th Floor New York NY 10014 1-646-580-3456 Anthony Casalena Officer Class A Common Stock Goldman Sachs & Co. LLC 200 West Street New York NY 10282 27103 1183859.04 89684219 06/17/2024 NYSE Class A Common Stock 08/18/2017 Acquired as compensation -- Restricted Stock Awards The Issuer N 27103 08/18/2017 Compensation N Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 03/06/2024 51278 1613087.94 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 03/07/2024 27690 884227.54 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 03/07/2024 52512 1683849.79 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 03/19/2024 100228 3433109.68 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 03/20/2024 31753 1084418.93 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 03/20/2024 62260 2137205.25 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 04/02/2024 51878 1880297.36 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 04/03/2024 30576 1116167.71 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 04/15/2024 45839 1614577.51 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 04/16/2024 36360 1291881.71 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 04/26/2024 40189 1428188.46 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 04/29/2024 27240 970239.77 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 05/09/2024 66983 2469428.77 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 05/10/2024 107946 4091768.69 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 05/22/2024 150000 6542400 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 05/23/2024 135063 5875037.91 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 06/05/2024 38724 1693377.29 Anthony Casalena Revocable Trust 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 06/06/2024 42586 1867115.03 The sales of shares set forth herein are made in connection with a selling plan dated 3/5/2024, that is intended to comply with Rule 10b5-1(c). All shares to be sold by the Anthony Casalena Revocable Trust. 06/17/2024 03/05/2024 Goldman Sachs & Co. LLC on behalf of Anthony Casalena