Japan banks gain access to OpenAI GPT-5.5 for cyber defense

Some Japanese financial institutions have been granted access to OpenAI's GPT-5.5 model to help strengthen their defences against cyberattacks, Japanese Finance Minister Satsuki Katayama said on Friday.

Katayama described the development as a significant advancement for Japan's financial sector following a meeting in Tokyo with Jason Kwon, OpenAI's chief strategy officer.

Government welcomes AI-driven cybersecurity support

Speaking to reporters after the meeting, Katayama said the decision would help financial institutions improve their ability to respond to cyber threats.

"This is a welcome development and a big step forward in strengthening Japanese financial institutions' ability to defend against cyberattacks," Katayama said, as cited in a Reuters report.

The finance minister's comments underscored the Japanese government's support for the use of advanced artificial intelligence tools in protecting critical financial infrastructure.

Katayama did not reveal which financial institutions had been granted access to the model.

As a result, the specific organisations currently using or testing GPT-5.5 for cybersecurity purposes remain undisclosed.

The announcement came after discussions between Japanese officials and OpenAI representatives regarding the application of advanced AI technology within the country's financial system.

Report points to Japan's largest banks

According to a report published by the Nikkei newspaper on Thursday, Japan's three largest banks are expected to receive access to OpenAI's latest model.

The report named MUFG Bank, Sumitomo Mitsui Banking Corp, and Mizuho Bank as the institutions expected to gain access.

Nikkei said GPT-5.5 is available only to trusted partners.

The publication also reported that the model is believed to be on par with Anthropic's Claude Mythos.

Neither Katayama nor OpenAI publicly confirmed the names of the institutions expected to receive access during Friday's remarks.

Open AI's business structure

OpenAI operates through a hybrid structure that combines a nonprofit foundation with a commercial, for-profit entity.

The company was initially supported by prominent technology figures, including Elon Musk and Sam Altman.

Over the years, OpenAI has developed a close partnership with Microsoft, helping bring its advanced AI technologies and models to a wider audience.

Focus on strengthening cyber resilience

The move reflects growing interest in using advanced artificial intelligence systems to strengthen cybersecurity capabilities within the financial sector.

Financial institutions continue to face increasingly sophisticated cyber threats, prompting investment in technologies designed to improve detection, monitoring, and response capabilities.

Katayama's comments indicated that Japanese authorities view access to OpenAI's latest model as a positive step toward improving cyber resilience across the country's financial system.

While details regarding implementation remain limited, the development marks a new stage in cooperation between Japanese financial institutions and OpenAI as the sector explores the use of advanced AI tools to enhance cybersecurity preparedness.