Adds declined to comment and did not respond to requests for comment from the 3 Japan megabanks and Anthropic

By Takaya Yamaguchi

TOKYO, May 13 (Reuters) - Japan's three largest banks are expected to gain access to Mythos, the artificial intelligence model developed by Anthropic, in about two weeks, a person with direct knowledge of the matter said.

Mythos is viewed by cybersecurity experts as posing significant challenges ​to the banking industry and its legacy technology systems, prompting a series of warnings from regulators ​and policymakers.

A string of U.S. banks have so far been given access to Mythos and Anthropic aims to expand access to European and UK banks, among other organisations, Reuters reported last month.

Mitsubishi UFJ Financial Group 8306.T and Mizuho Financial Group 8411.T declined to comment. Sumitomo Mitsui Financial Group 8316.T and Anthropic did not respond to requests for comment.

On Tuesday, Japanese Finance Minister Satsuki Katayama met U.S. Treasury Secretary Scott Bessent and later said Japan would establish a public-private working group this week to address cybersecurity risks to the Japanese financial system posed by Mythos.

The group's first meeting will be held on Thursday.