As filed with the Securities and Exchange Commission on December 8, 2025. Registration Statement No. 333-290415 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 Andersen Group Inc. (Exact name of Registrant as specified in its charter) (State or other jurisdiction of (Primary Standard Industrial (I.R.S. Employer incorporation or organization) Classification Code Number) Identification Number) Delaware ...

Table of Contents As filed with the Securities and Exchange Commission on November 19, 2025. Registration Statement No. 333-290415 UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 AMENDMENT NO. 1 TO FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 Andersen Group Inc. Mark L. Vorsatz Chairman and Chief Executive Officer Andersen Group Inc. 333 Bush Street Suite 1700 San Francisco, California 94104 (415) 764-2700 (Name, address, including zip code, and telephone number, ...

Registration Statement No. 333- Table of Contents As filed with the Securities and Exchange Commission on September 19, 2025. FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 Andersen Group Inc. (Exact name of Registrant as specified in its charter) Delaware 7389 33-4630773 (State or other jurisdiction of (Primary Standard Industrial (I.R.S. Employer incorporation or organization) Classification Code Number) Identification Number) Andersen Group Inc. 333 Bush Street Suite 1700 San Francisco, ...