GPT-5.5-Cyber will reach MUFG, SMBC and Mizuho through a verified-defender programme, the finance minister said, as Tokyo treats frontier AI as both threat and shield.
The same models that make cyberattacks cheaper to run are now being handed, deliberately, to the people defending against them. Japan’s three megabanks will gain access to OpenAI’s latest model for cyber defence, Finance Minister Satsuki Katayama said, in a move that treats a frontier system as critical national infrastructure rather than a consumer product.
The model, GPT-5.5-Cyber, will reach MUFG Bank, Sumitomo Mitsui Banking Corporation and Mizuho Bank through what OpenAI calls its “Trusted Access for Cyber” programme, a framework built to put the most capable tools only in the hands of verified defenders.
The logic is gatekeeping: a model good enough to find vulnerabilities at scale is, by definition, dangerous if it reaches the wrong users, so access is rationed to institutions that can be vetted.
The 💜 of EU techThe latest rumblings from the EU tech scene, a story from our wise ol' founder Boris, and some questionable AI art. It's free, every week, in your inbox. Sign up now!The arrangement did not come together at the technical level alone. Katayama and US Treasury Secretary Scott Bessent were directly involved in the discussions that opened the collaboration, lending it the character of a government-to-government understanding as much as a commercial supply deal.
