Japanese Finance Minister Satsuki Katayama said on Friday that a number of financial institutions in Japan have been granted access to OpenAI’s GPT-5.5 model as part of efforts to strengthen defenses against cyberattacks.
Speaking after a meeting in Tokyo with Jason Kwon, OpenAI’s chief strategy officer, Katayama described the development as a positive step for the resilience of the country’s financial system. She said access to the model is intended to assist institutions in bolstering their cybersecurity capabilities.
"This is a welcome development and a big step forward in strengthening Japanese financial institutions’ ability to defend against cyberattacks," Katayama said.
Katayama did not identify which institutions had been granted access to the model. A separate report in the Nikkei newspaper indicated that Japan’s three largest banks - MUFG Bank, Sumitomo Mitsui Banking Corp and Mizuho Bank - were expected to obtain access to the latest OpenAI model. The report also noted that the model is available only to trusted partners and is believed to be comparable to a rival model from Anthropic, Claude Mythos.
The minister’s comments followed the private meeting with OpenAI’s strategy lead in Tokyo, and focused on the role of advanced AI tools in improving the cyber resilience of financial firms. Beyond stating that access had been provided to some Japanese financial institutions, Katayama offered no further specifics about which organizations were involved or the exact nature of their access arrangements.
The Nikkei’s reporting, referenced by officials, framed the expected recipients as the country’s largest banks, though that expectation has not been publicly confirmed by the finance minister. The availability of GPT-5.5 only to trusted partners was highlighted as a limiting factor in determining how broadly the model is being deployed within Japan’s financial sector.
Officials characterized the step as aimed at shoring up defenses against cyber threats, while leaving open questions about implementation, oversight and the extent of access across the banking industry.