Table of Contents As filed with the Securities and Exchange Commission on September 28, 2023. Registration Statement No. 333-274421 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Amendment No. 2 FORM S-1 REGISTRATION STATEMENT Under THE SECURITIES ACT OF 1933 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Copies to: Lewis J. Geffen, Esq. Daniel A. Bagliebter, Esq. Nishant M. Dharia, Esq. Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. One Financial Center ...

Table of Contents As filed with the Securities and Exchange Commission on September 8, 2023. Registration Statement No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-1 REGISTRATION STATEMENT Under THE SECURITIES ACT OF 1933 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation or organization) Delaware 2834 26-1824804 (Primary Standard Industrial Classification Code Number) (I.R.S. Employer Identification Num ...