OpenAI gives Japan’s megabanks its newest model for cyber defence Japan’s three megabanks will gain access to OpenAI’s GPT-5.5-Cyber model for cyber defence through a “Trusted Access for Cyber” program, aimed at verified defenders. This government-brokered deal treats advanced AI as critical national infrastructure, but raises concerns about creating a security gap for smaller financial institutions.

• Japan’s MUFG Bank, Sumitomo Mitsui Banking Corporation, and Mizuho Bank will access OpenAI’s GPT-5.5-Cyber model.
• The model is provided through OpenAI’s “Trusted Access for Cyber” program for vetted defenders.
• The deal involved direct discussions between Japan’s Finance Minister Satsuki Katayama and US Treasury Secretary Scott Bessent.
• This initiative is part of Japan’s broader push to address AI-related cyber risks, including a public-private working group.
• Anthropic’s Claude Mythos is another AI model being considered for similar defensive access by Japanese institutions.
• A potential structural risk is the widening security gap between large, vetted institutions and smaller banks or fintech startups.
• The immediate effect is that three of the world’s largest banks will use a frontier AI model for their defences. Continue reading https://thenextweb.com/news/openai-japan-megabanks-cyber-model