Which company has the best AI model end of May?

Platform comparison

Active sub-markets

Market context

The market resolves on which company has the top-ranked model on the Chatbot Arena leaderboard when checked at 12:00 pm ET on 31 May, so the last week of the month matters more than longer-run reputation. The current 1% price on anyone other than Anthropic implies traders see the board as heavily entrenched, and the recent Polymarket pricing is consistent with that view: Anthropic is far ahead for both end-of-May and end-of-June contracts, with Google the main alternative. That leaves only a narrow route for a late leaderboard shuffle.

In practice, these markets usually track one of two things: a fresh model release that lands well in Arena voting, or a ranking adjustment after enough new comparisons come in. The key watchpoint is whether Google, OpenAI, or another lab ships a new flagship before the cut-off, since the Arena table is sensitive to prompt quality, coding, and general chat performance rather than to a single benchmark. Overchat’s May 2026 roundup has framed Claude Opus 4.7, Gemini 3.1 Pro and GPT-5.5 as the current leaders in coding, reasoning and broad capability, which underlines how close the race is below the top line even if Anthropic remains the market favourite.

For traders, the relevant catalyst is the leaderboard itself: any model announcement, refresh, or notable score update before 31 May can shift the rank column quickly. The resolution depends specifically on the “Text Arena | Overall” table with style control off, so late-day updates and tie-breaks by Arena score can matter if two models sit level on rank. If there is no major release from a rival, the existing 97%/1% market split suggests the status quo is the base case.

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Methodology

This page is a comparison snapshot: one live quote (Polymarket), four reference venues with their key attributes, and a single execution path — every trade button routes to PolyGram, which mirrors the Polymarket order book directly.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Where can I trade this market with the lowest fees?

On PolyGram, 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?

PolyGram 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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.