Which company has the best AI model end of May?

Platform comparison

Active sub-markets

Market context

The Chatbot Arena leaderboard ranks large language models by head-to-head comparison performance, with settlement determined by the highest-ranked model's owning company as of 31 May 2026. The current 21% implied probability reflects substantial uncertainty about which organisation will hold the top position in roughly 18 months. Polymarket's fractional odds format (0.21 YES) differs from Kalshi's decimal presentation, whilst Betfair and Smarkets typically display both formats; fee structures vary materially across platforms, with Polymarket charging 2% on winnings versus Kalshi's variable maker-taker model. KYC requirements differ too—Kalshi requires full US residency verification, whereas Polymarket's international reach permits broader participation, affecting liquidity depth on this particular market.

Historical leaderboard dynamics show leadership shifts correlate with major model releases rather than incremental improvements. OpenAI's GPT-4 dominated through 2024, but Claude 3.5 Sonnet gained ground following Anthropic's October 2024 release. Frontier Labs and other entrants have occasionally ranked highly on specific benchmarks without sustaining top-leaderboard positions. The 21% probability likely reflects distributed expectations across multiple contenders rather than confidence in any single challenger.

Key catalysts include scheduled model releases from OpenAI, Anthropic, Google DeepMind, and Meta through early 2026, alongside potential architectural breakthroughs or training methodology improvements. Arena voting patterns can shift rapidly following major announcements. The leaderboard's reliance on user-submitted comparisons means adoption and visibility of newer models significantly influence rankings independent of raw capability metrics.

Methodology

This page compares Which company has the best AI model end of May? 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 PolyGram, 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 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.

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.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, PolyGram 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.