In a recent move, some Japanese financial institutions have been given access to GPT-5.5, which is a model by U.S. artificial intelligence company OpenAI, in order to safeguard against cyberattacks, Satsuki Katayama, the Japanese finance minister, said on May 29, 2026, after meeting with the chief strategy officer of the U.S. company.
The access to access to GPT-5.5 will lead to new AI models capable of coding at a high level being released, giving hackers extraordinary ability to detect cybersecurity threats and develop ways to attack them.
The early access when it comes to the new models being available only to trusted partners is one line of defence for the banks and various other companies deemed to be at risk of being destabilised.
Katayama has declined to name any of the financial institutions but said the accessibility they were receiving was a major step forward in improving Japanese financial institutions’ capacity to safeguard against cyberattacks. She was addressing reporters after meeting with the chief strategy officer at OpenAI, Jason Kwon, in Tokyo.
The three largest banks of Japan, MUFG Bank and Sumitomo Mitsui Banking Corp., as well as Mizuho Bank, will set to get access to the latest model of OpenAI, which is thought to be on a level playing field with the model used by rival Anthropic’s Claude Mythos, the Nikkei newspaper stated on May 28, 2026.
MUFG, as well as Mizuho, have declined to comment. Sumitomo Mitsui Banking was not readily accessible for comment.
Mythos was also anticipated to be made available to government and financial institutions of Japan so as to strengthen their defences, Katayama.
This month Japan created a public-private working group to deal with cybersecurity dangers to the financial system from Mythos, in an effort to mitigate AI threats.
The access to Japanese financial institutions was granted after formal negotiations between the Japanese and U.S. governments, based on European companies’ earlier access.