Japan megabanks prepare for Anthropic Mythos access by May 2026, Nikkei reports

Japan’s three largest banks are set to gain access to Anthropic’s Mythos artificial intelligence model as soon as May 31, 2026, the Nikkei reported, potentially making them the first Japanese companies to use the cybersecurity-focused system. The banking units of Mitsubishi UFJ Financial Group (8306.T), Sumitomo Mitsui Financial Group (8316.T) and Mizuho Financial Group (8411.T) were likely informed of the plan by U.S. Treasury Secretary Scott Bessent during a May 12 meeting in Japan, Nikkei said. Mythos is designed for defensive cybersecurity work, but Anthropic has said a preview found major vulnerabilities across leading operating systems and web browsers. Japanese Finance Minister Satsuki Katayama said after meeting Bessent on May 12 that Japan would form a public-private working group in the week of May 11 to address financial-system cybersecurity risks tied to Mythos. The group’s first meeting is expected on May 14.