Black Spade Acquisition III Co(BIIIU) - Prospectus(update)

As filed with the U.S. Securities and Exchange Commission on December 12, 2025 Registration No. 333- 290602 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 Black Spade Acquisition III Co (Exact Name of Registrant as Specified in Its Charter) Cayman Islands (State or other jurisdiction of incorporation or organization 6770 (Primary Standard Industrial Classification Code Number) N/A (I.R.S. Employer Id ...