The U.S. government has mandated the shutdown of Anthropic’s two leading artificial intelligence models, Fable 5 and Mythos 5, citing national security issues linked to a potential jailbreak vulnerability. This decision has resulted in a notable decline in the company’s pre-initial public offering (IPO) share value.
On Friday, Anthropic was informed of the directive, which prohibited access to these models for foreign nationals, both domestically and internationally. Following this order, the Anthropic perpetual contract on Hyperliquid, which reflects market expectations of the company’s equity value, fell by 3.7% to approximately $1,627. This decline comes after the contract had recently reached record highs exceeding $1,800.
The government’s action was prompted by the discovery of a method to bypass the security measures of Fable 5. Anthropic has contested this directive, arguing that the government has only presented verbal evidence of a limited vulnerability that is already known and can be identified by other AI models, including OpenAI’s GPT-5.5.
Anthropic has characterized the alleged jailbreak as a narrow issue, involving the model’s ability to read and correct software flaws—an operation that is commonplace among AI systems. The company has expressed concern that the standards being applied could stifle innovation across the AI industry, potentially halting the deployment of new models.
Founded on principles of safety in AI development, Anthropic is now publicly challenging the government’s directive. The company plans to provide a detailed analysis of the jailbreak claim within the next 24 hours, which may influence the government’s stance on the matter.
The implications of this shutdown extend beyond Anthropic itself, as the crypto market is reacting negatively to the news, raising questions about the company’s valuation and future IPO prospects. The outcome of Anthropic’s technical rebuttal could determine whether the government’s order remains in effect or is modified, which would significantly impact the company’s public listing ambitions.
The U.S. government's order to shut down Anthropic's Fable 5 and Mythos 5 AI models due to security concerns has led to a decline in the company's pre-IPO share value. Anthropic disputes the directive, arguing the vulnerabilities cited are limited and already known, raising broader questions about the implications for the AI industry.