SK Telecom Cut From Anthropic's Mythos Program Over China Ties

South Korea's largest wireless carrier is now publicly identified as the company whose access to Anthropic's most capable model triggered a chain of events that ended with the White House pulling that model offline for all foreign nationals. Wired named SK Telecom as the company at the center of the dispute: the carrier was added to Anthropic's Project Glasswing in early June, the program through which Anthropic distributes its Mythos model for vulnerability detection work. The White House asked Anthropic to revoke SK Telecom's access shortly after that expansion, over alleged ties to China, and Anthropic complied immediately. No export controls were threatened at that point. Days later, the White House took Mythos and Fable 5 offline for all foreign nationals.

The China ties the White House flagged look thin for SK Telecom on its own terms. The company generated roughly $1.9 million in Chinese revenue in 2024 and employs seven people in the country, according to its annual report. The historical picture is more layered. SK Telecom formed a wireless joint venture called UNISK with state-owned China Unicom in 2004, invested $1 billion in China Unicom convertible bonds in 2006, and that stake converted to roughly 6.6% before being sold in 2009 for $1.3 billion. A residual UNISK investment worth roughly $17 million still appears in its 2025 U.S. Securities and Exchange Commission filing. SK Telecom is also part of the larger SK Group conglomerate, whose affiliates have business interests in China across semiconductors and energy, according to reporting by Tom's Hardware. SK Telecom has denied the allegations, reportedly telling a Korean newspaper that anonymous claims in foreign media "lack verified facts" and that it has no ties to China.

The broader Mythos situation has a separate thread. The White House received a report from Amazon, Anthropic's largest investor, flagging a guardrail bypass in Fable 5. Both Mythos and Fable 5 remain offline for foreign nationals as Anthropic and the White House negotiate. Anthropic opened its Seoul office during this period even as Korean access to its top models was cut.

What the reporting does not give you is any clarity on what specific intelligence prompted the White House to single out SK Telecom from the roughly 150 Project Glasswing participants, whether the concern centers on the carrier's own limited China exposure or SK Group's wider footprint, and whether the commercial or investment relationship between SK Telecom and Anthropic is at risk beyond model access.

The stakes are clearest for companies in allied nations with diversified conglomerate structures: if access criteria end up hinging on group-level China exposure rather than a specific entity's direct ties, the bar for international participation in programs like Project Glasswing rises sharply. How Anthropic and the White House resolve this case will signal whether frontier AI research partnerships with allied-nation industrial companies remain viable, or require a restructuring that most conglomerates cannot practically manage.