Claude Mythos released by…?

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Active sub-markets

Market context

Anthropic confirmed on 26 March 2026 that Claude Mythos, a model detailed in a data leak the same day, exists and is undergoing early access testing. The leak described the model as representing a substantial capability jump in coding, reasoning, and cybersecurity tasks. The market resolves affirmatively if Anthropic releases this model or formally confirms a released model matches the leaked specifications before 30 April 2026.

Historical precedent suggests caution about near-term release timelines following unplanned disclosures. When OpenAI's GPT-4 architecture details surfaced ahead of schedule in early 2023, the company maintained its original release schedule but faced pressure to accelerate announcements. Anthropic's own Claude 3 family rollout occurred across several weeks in March 2024, with the most capable variant (Opus) arriving last. Early access programmes typically precede general availability by weeks or months rather than days, making a full public release within five weeks from confirmation unlikely absent extraordinary circumstances.

Traders should monitor Anthropic's official announcements and developer platform updates for any Mythos availability changes. The company typically signals model releases through its website and API documentation rather than press releases. Competitor moves matter too: if OpenAI or Google announce major model releases in April, Anthropic might accelerate or delay Mythos timing. The current 0% crowd probability reflects the compressed settlement window and historical patterns where "early access" rarely transitions to general release within such narrow timeframes. Any official statement narrowing the release date or expanding access beyond closed testing would materially shift odds.

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 Best Prediction Markets 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 Best Prediction Markets 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.

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.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Best Prediction Markets UK triggers a quick verification flow that finishes in minutes.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.