SC II Acquisition Corp-A美国存托股票招股说明书(2025-12-04版)

SCII Acquisition Corp. 15,000,000 Units This Prospectus Supplement No. 1 (this “Supplement”) relates to the prospectus of SC II Acquisition Corp. (the “Company”), datedNovember 25, 2025 (the “Prospectus”), relating to the initial public offering of the Company’s securities. This Supplement should be read in conjunction with the Prospectus and is qualified by reference to the Prospectus, except to the extentthat the information in this Supplement supersedes the information contained in the Prospectus, and may not be delivered without the This Supplement is being filed to update and supplement the information contained in the table that sets forth the names of theunderwriters appearing in the “Underwriting” section on page 189 of the Prospectus as follows: Underwriters We are an “emerging growth company” and a “smaller reporting company” under applicable federal securities laws and willbe subject to reduced public company reporting requirements. Investing in our securities involves a high degree of risk. See“Risk Factors” beginning on page 47 for a discussion of information that should be considered in connection with an Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved ofthese securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminaloffense. The date of this Prospectus Supplement No. 1 is December 4, 2025