Japan's Banks Unite Over AI Threat From Anthropic's Mythos Model

Claude Mythos Fears Startle Japan's Financial Services Sector reports that global financial institutions are panicked over Anthropic's new superhacker AI model, while cyber experts remain more measured. On 24 April 2026, Japan’s finance minister, the governor of its central bank, the presidents of its three megabanks, and a senior executive of its stock exchange gathered at the Financial Service Agency in Tokyo to form a working group addressing the cyber threat Mythos may pose.

According to Anthropic, during testing the Mythos model identified previously unknown vulnerabilities in every browser and OS it was presented with, including a vulnerability chain that linked four issues in a single exploit. At a press conference, finance minister Satsuki Katayama described Mythos as “a crisis that is already upon us.” Cybersecurity experts question whether Mythos represents a crisis point for Japan, noting that access to the model has been restricted to a tight circle of organisations.