Claude Mythos released by…?

Platform comparison

Active sub-markets

Market context

Anthropic confirmed on 26 March 2026 that Claude Mythos, a model described internally as a significant leap forward in coding, reasoning, and cybersecurity capabilities, exists and is undergoing early access testing following an unplanned data disclosure. The market asks whether Anthropic will formally release this model—or explicitly confirm a released model is Mythos itself—by 30 April 2026. At 0% implied probability across major books, traders are pricing near-zero chance of a public launch within five weeks.

Anthropic's release cadence offers relevant precedent. Claude 3 arrived in March 2024 with a three-model tier (Opus, Sonnet, Haiku) announced simultaneously; Claude 3.5 Sonnet followed in June 2024, then Claude 3.5 Haiku in November 2024. None of these followed a pre-release leak. When models do launch, Anthropic typically announces via blog post and API availability on the same day. The company has historically taken 6–12 months between major capability jumps, suggesting Mythos—if positioned as a generational advance—may follow a longer development cycle than the current market window allows.

Watch for three signals: an official Anthropic announcement (blog, earnings call, or press release), API availability through claude.ai or their developer console, and third-party confirmation of model access. Kalshi's fee structure (0.4% maker/taker) and KYC requirements differ from Polymarket's (2% fees, lighter verification), affecting break-even thresholds on low-probability outcomes. Betfair and Smarkets offer decimal odds formats that may clarify the true long-shot nature of this position. The settlement window closes 30 April 2026; any announcement after that date resolves to No.

Methodology

This page compares Claude Mythos released by…? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. Live odds come from the Polymarket order book; the other venues' contract details are maintained manually because their APIs aren't directly comparable. Every CTA routes to Kalshi Alternative UK, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

FAQ

Where can I trade this market with the lowest fees?

On Kalshi Alternative 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, Kalshi Alternative 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.