U.S. authorities cut off all foreign access to Anthropic's two newest frontier AI models — Mythos 5 and Fable 5 — on Friday, June 12, 2026, at 5:21 p.m. Eastern, forcing the company to disable both products for every customer, a restriction that reached even Anthropic's own foreign-born employees, according to the company's statement cited by the South China Morning Post. For Korean institutions that had just been granted early access, the shutdown was abrupt. The more sensitive question now circulating in Seoul is whether a Korean company is the reason the ban happened at all.
The China-link allegation
The Washington Post reported on June 15, citing two unnamed White House officials, that the Trump administration had weighed export controls for weeks before pulling the models, and that the decisive trigger was Anthropic sharing technology with a firm suspected of links to China. According to the Post's account as relayed by Chosun Biz, Anthropic had presented the administration a list of 111 institutions it planned to add to Project Glasswing, and disclosed that roughly 50 additional entities had already been granted access to Mythos 5 — after the company warned the model could sharply boost hackers' offensive capabilities. When the administration reviewed the full list, it identified one entry as "a South Korean telecommunications company suspected of ties to China," the Post reported. A person familiar with Anthropic's internal handling said the company immediately revoked that institution's Mythos access, per the same report.
The Post did not name the company. Speculation in Korean media has narrowed toward SK Telecom (017670.KS), Korea's largest wireless carrier, after KT and LG Uplus — the country's second- and third-largest mobile operators — both said they had never been granted Mythos access, according to Chosun Biz.
SK Telecom's position — and its Anthropic exposure
SK Telecom disputes the inference. The carrier said on June 4 it had joined Project Glasswing — Anthropic's Mythos-based security consortium — and obtained early access to "Claude Mythos." But an SK Telecom official told Chosun Biz the report does not refer to the company and that it is unrelated to the matter, noting the June 12 restriction on foreign-national access was "a blanket measure" applied uniformly, with no separate notice to SK Telecom.
What raises the stakes is how central Anthropic has become to SK Telecom's valuation story. The carrier invested USD 100 million (about ₩132 billion) in Anthropic on Aug. 13, 2023, taking a roughly 2% stake, and the two signed a partnership to build a telco-specific large language model, per SK Telecom's own press release and Chosun Biz. After Anthropic's subsequent fundraising — including a Series H round in late May — SK Telecom's diluted stake of roughly 0.7% was carried at around ₩1.376 trillion (about USD 900 million), more than ten times its original cost in won terms, according to reporting on the holding. That stake is an equity position, not a license to the models, so the export ban does not directly impair its book value — but any confirmed China-link finding would be a reputational complication for SK Telecom's most celebrated bet.
Project Glasswing was expanded on June 2 to 150 institutions across 15 countries; Chosun Biz reported the Korean participants as Samsung Electronics (005930.KS) and SK Hynix (000660.KS) — the country's two largest memory-chip makers — alongside SK Telecom, plus KISA (Korea Internet & Security Agency, the state cybersecurity body). The Korea Times separately listed SK Telecom, Samsung Electronics and KISA among those granted access.
A competing explanation
The China angle is not the only theory. The Wall Street Journal reported, citing multiple sources, that the move originated with a conversation between Amazon CEO Andy Jassy and U.S. Treasury Secretary Scott Bessent, in which Jassy relayed that Amazon researchers had repeatedly queried Anthropic's Fable 5 model to extract restricted cyberattack information it was designed not to provide.
Why it matters
According to the Washington Post, this is the first known instance of the White House invoking national-security authority to force a leading U.S. AI company to withdraw a flagship product, a move the Post said "may set a new precedent" for direct government oversight of frontier-model development and distribution. The Korean dimension echoes the October 2022 U.S. chip export controls, which forced Samsung Electronics and SK Hynix to seek Validated End User waivers for their China fabrication plants — exemptions ultimately granted in 2023 — a reminder that U.S. technology restrictions routinely catch Korean firms in their reach.
The concrete data point to watch: Korea's Ministry of Science and ICT (the country's technology and telecom regulator) said it is verifying the facts and weighing responses under the coordination of the National Security Office, per the Korea Times. Whether that review — or any subsequent U.S. or Anthropic disclosure — names the implicated institution will confirm or refute the SK Telecom speculation.
This article is for informational purposes only and does not constitute investment advice.
