Anthropic launches Claude Fable 5.2 and Mythos 5.2 at 20% lower prices as its IPO nears

Anthropic (ANT) released Claude Fable 5.2 and Claude Mythos 5.2 on Monday, with its IPO possibly only a week away.

Fable and Mythos are the same underlying model. Fable has safeguards against misuse in cybersecurity and biology, so anyone can use it. Mythos goes only to vetted organizations through Anthropic's Life Sciences and Cyber Verification Programs.

The new models are cheaper. Fable 5.2 costs 20% less than Fable 5.1, the company says. It is billed by the token, a small piece of text a model reads or writes:

• Price: $8 per million input tokens and $40 per million output tokens, down from $10 and $50.
• Speed: output up to 30% faster than the 5.1 models.
• Fast mode: up to 2.5 times faster, at twice the standard price.

Anthropic says Fable 5.2 scored 49.1% on FrontierCode, a test of whether open-source maintainers would accept a model's code changes. That puts it ahead of the best score of GPT-6 Astra from OpenAI, at 42.8%.

The company still points most users to Claude Opus 5.5 for everyday coding and knowledge work. Fable is meant for the hardest problems in engineering, math and science.

This is Anthropic's first frontier release since CEO Dario Amodei called in September for the industry to slow AI development down. The company says it ran extensive safety tests first and built new checks for behaviors such as a model escaping its test environment.

Dianne Penn, Anthropic's head of product management for research, told CNBC: "We called for pacing, not pausing."

The Fable and Mythos models helped fuel the company's rise this year. Its amended prospectus shows revenue of $33.24B for the nine months to September 30, up about 1,200% from a year earlier.

CNBC has reported that Anthropic is aiming for a valuation of $1T to $1.5T, down from the $2T talked about in recent months. After last week's tech selloff, some investors now call even $1.5T a stretch.

Executives are about to start the IPO roadshow, the round of meetings with investors before the shares are priced. The stock will list on the Nasdaq under the ticker ANT.

Sources & Further Reading

1. "Introducing Claude Fable 5.2 and Claude Mythos 5.2." Anthropic. November 9, 2026.
2. "Anthropic releases first frontier models since Amodei's call for slowdown as IPO buzz builds." CNBC. November 9, 2026.
3. "Claude Fable." Anthropic. November 9, 2026.
4. "Investors brace for lower Anthropic valuation, calling $1.5 trillion a 'stretch'." CNBC. November 6, 2026.