Prediction market platform Kalshi handled nearly $18 billion in notional trading volume in May, Messari senior research analyst Austin Weiler wrote in a June 3 post on X.
With nearly $17.9 billion in May volume, Kalshi took about 58% of the prediction market category, while Polymarket ranked second with $8.8 billion, or 28%, the post reads.
- Limitless, a prediction market platform launched on Base, ranked third with $1.7 billion, while BNB Chain's Predict.Fun had $1.1 billion, Opinion had $700 million and other venues together had $900 million.
- The data, sourced from Dune, uses notional volume, meaning shares traded multiplied by $1 resolution value, not the actual amount of U.S. dollars exchanged at trade prices.
Chart comparing May 2026 prediction market volume. Source: X
As Weiler explained, Kalshi has now led the category for nine straight months and held majority share for two months in a row.
Austin Weiler
Sports appear to be driving most of Kalshi's lead. Sports and Exotics, Kalshi's category for regular sports markets and combo-style bets such as parlays, generated $15.3 billion in May, or about 85% of the platform's monthly volume, according to the post.
- Crypto was Kalshi's second-largest category at $2 billion, or about 11% of the total.
Polymarket, the crypto-native prediction market best known for on-chain event betting, moved the other way in May as its volume fell 13% month over month to $8.8 billion, marking its second straight monthly decline.
- Limitless grew 3% month over month to $1.7 billion, moving ahead of Predict.Fun, which fell 29% to $1.1 billion.
- Hyperliquid, the decentralized perpetual futures exchange and Layer-1 blockchain that recently moved into prediction markets, wasn't shown in the chart but generated $92 million in its first month.
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