As filed with the Securities and Exchange Commission on January 29, 2024. Registration No. 333-276495 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Amendment No. 2 to FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 Alto Neuroscience, Inc. (Exact Name of Registrant as Specified in Its Charter) (State or Other Jurisdiction of Incorporation or Organization) Delaware 2834 83-4210124 (Primary Standard Industrial Classification Code Number) (I.R.S. Employer Identificatio ...