President Joe Biden is expected to block the $14.1 billion acquisition of U.S. Steel by Japan's Nippon Steel, citing national security concerns. The Committee on Foreign Investment in the United States (CFIUS) will present its decision to Biden by December 22-23, after which he has 15 days to announce his ruling. Both companies are prepared for a legal challenge if the merger is blocked. Nippon Steel remains optimistic about completing the acquisition by the end of 2024, despite growing bipartisan opposition to foreign control of critical U.S. industries.