Claude Mythos released by…?

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Active sub-markets

Market context

Anthropic confirmed on 26 March 2026 that Claude Mythos, an unreleased model described in a data leak, exists and is undergoing early access testing. The leak detailed substantial improvements in coding, reasoning, and cybersecurity capabilities relative to current Claude versions. The company has not yet announced a public release date, leaving the settlement window—which closes 30 April 2026—with roughly five weeks for an official launch announcement.

Historical precedent suggests caution around the 0% implied probability. When OpenAI's GPT-4 leaked in early 2023, the company released it within weeks rather than shelving the project entirely. Similarly, Anthropic's own Claude 3 family was released publicly months after internal testing phases became known. However, the compressed timeline here differs materially: a five-week window is tight for enterprise go-to-market execution, regulatory sign-off, and infrastructure scaling. Anthropic has historically favoured measured rollouts over rushed launches, which may explain the current crowd scepticism.

Traders should monitor Anthropic's official channels and earnings communications for release timing signals. The company typically announces availability through its website and API documentation simultaneously. Watch for subsidiary indicators: expansion of Claude's API rate limits, recruitment announcements for support teams, and statements from Anthropic leadership at industry conferences. Any scheduled earnings call or investor update before end-April could serve as a catalyst. The Fortune article from the leak date remains the most recent public confirmation; absence of follow-up announcements in the subsequent weeks suggests internal deliberation over launch strategy rather than imminent release.

Methodology

This page reviews Claude Mythos released by…? across five venues. We show live odds for Polymarket-based markets (sourced from the Polygon order book); for other venues we list platform attributes, since the comparable contracts are not exposed via a public API on every venue. Every CTA points at Polymarket Review UK — the application we operate, where you trade directly against the Polymarket order book at 0% fees.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

Where can I trade this market with the lowest fees?

On Polymarket Review UK, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket Review UK is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

What does it cost to trade on Polymarket Review UK?

Zero. Polymarket Review UK routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.