SK Telecom's Suspected China Ties Were the Hidden Trigger of Anthropic's Fable 5 and Mythos Shutdown, New Report Reveals

New reporting from The Decoder reconstructs the two-step process behind the Anthropic model shutdown: US officials first directed Anthropic to revoke Claude Mythos access only for SK Telecom — a $100M Anthropic investor since 2023 and Project Glasswing partner — after identifying suspected China ties, and Anthropic complied the same day. That same week, Amazon and five other partners separately flagged vulnerabilities in Fable 5, prompting the White House to order nationality-based access restrictions; rather than implement the nationality check, Anthropic chose to disable both models globally. SK Telecom denied any Chinese connections to Korean media, noting it uses no Huawei or ZTE core equipment, though the company held a stake in China Unicom in 2006 that US officials may be citing.