OpenAI is providing its GPT-5.5-Cyber model to Japan's three largest banks-MUFG Bank, Sumitomo Mitsui Banking Corp., and Mizuho Bank-starting May 2026. The deal follows US Treasury Secretary Scott Bessent's recent visit to Tokyo.
Anthropic's Claude Mythos, which autonomously detects zero-day vulnerabilities, will also be deployed to the same institutions. A new public-private working group with 36 members, including these banks and AI firms, is being formed to coordinate security efforts.
Japanese regulators have expressed concern about potential misuse of these AI models, and the working group is developing guardrails.