Anthropic Suspends Fable 5, Mythos 5 After US Government Order Amid Record SpaceX Debut — Retail Traders Eyeing Anthropic IPO

• Anthropic blocked Fable 5 and Mythos 5 for all users on Friday after a US export control request invoked national security authorities.
• Anthropic said the jailbreak uncovered only minor, already-known weaknesses that could be found in other publicly accessible models.
• Retail traders predicted a future Anthropic IPO and a second-quarter 2026 operational profit fueled by Claude and Claude Code.

Anthropic (ANTHZZ) cut off access to its Fable 5 and Mythos 5 artificial intelligence models to all customers late Friday, after the U.S. government issued an export control directive citing national security authorities, the company said.

The order covers "any foreign national, wherever located, inside or outside the United States, including foreign national Anthropic employees," Anthropic said in a statement, adding that compliance meant turning off the models entirely for all users. The company said there was no impact on access to all other Anthropic models.

The company said the government’s concern was about a way to “jailbreak” Fable 5, but it challenged the seriousness of the findings.  Anthropic said it reviewed a demonstration showing the technique being used to surface "a small number of previously known, minor vulnerabilities" and claimed other publicly available models can be used to find the same issues without any bypass.

Anthropic said the government has only presented evidence so far for a narrow jailbreak that essentially asked the model to read a codebase and fix software flaws, a capability it said is “widely available from other models, including OpenAI’s (OPEAZZX) GPT-5.5” and routinely used by security teams.

Anthropic And The US Government At Odds

The directive was issued by Commerce Secretary Howard Lutnick with input from officials at the Commerce Department’s Bureau of Industry and Security, according to NBC News. 

This comes after a rocky relationship between Anthropic and Washington. Anthropic has sued the administration over the designation, which the Defense Department had previously labeled Anthropic a “supply chain risk” after talks between the two sides fell apart.

Anthropic said it disagreed with removing a commercially deployed model over a narrow finding and called the incident a likely "misunderstanding," saying it was working to restore access as soon as it could. The shutdown came on the same day SpaceX began trading on the Nasdaq under the ticker SPCX. Shares opened at $150 after pricing at $135 in one of the biggest IPOs in history, and closed up 19% to $161, giving the company a value of nearly $1.77 trillion.

Robert Greifeld, a former Nasdaq chief, told CNBC on Friday that he expected Anthropic and OpenAI to follow SpaceX to public markets this year. 

What Are Retail Traders Betting on? 

Retail traders attributed the news to expectations of a possible future IPO listing for Anthropic (ANTHZZX), citing the company's projected first quarterly operating profit at roughly $10.9 billion in revenue and about $559 million in operating income for the second quarter of 2026, driven by growth in Claude and Claude Code.

The view was a rotation call, another trader said, with capital better placed ahead of an Anthropic listing than in SpaceX at current levels.

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