WASHINGTON, D.C. — Combined monthly global trading volume on Kalshi and Polymarket increased from less than $5 billion in September 2025 to about $24 billion in April 2026, according to a Pew Research Center analysis of data from The Block. The data covers activity on both platforms from July 2024 through early May 2026.
Trading volume in this context reflects notional taker volume in U.S. dollars, with each contract counted at its $1 notional value rather than the price at which it traded. Prediction markets like Kalshi and Polymarket allow users to buy and sell contracts tied to binary outcomes, with prices between $0 and $1 representing the market’s perceived probability of an event occurring.
In April 2026, Polymarket International reported $9 billion in trading volume, while Polymarket US, the version regulated by the U.S. Commodity Futures Trading Commission (CFTC), recorded $1.3 billion. Kalshi, which is also regulated by the CFTC, contributed the remainder of the combined $24 billion total. Americans can access Polymarket International using a virtual private network, though that version of the platform is not CFTC-regulated.
Since July 2024, sports, politics, and cryptocurrency have accounted for 91% of Kalshi’s global trading volume and 90% of Polymarket’s. Sports dominated activity on Kalshi, representing 80% of its volume, compared to 39% on Polymarket. Cryptocurrency trading made up 7% of Kalshi’s volume but 20% of Polymarket’s. Political markets accounted for 4% of Kalshi’s total volume and 32% of Polymarket’s.
During the 2024 U.S. election period, political markets saw heightened interest. In October and November 2024, political contracts represented 90% of Kalshi’s trading volume and 65% of Polymarket’s. At that time, Kalshi had not yet introduced sports markets, which it later launched as part of its expansion.
Both platforms also offer markets on other topics, such as weather forecasts and events tied to media appearances or public statements. However, trading on these subjects constitutes a small fraction of overall activity on both Kalshi and Polymarket. For comparison, legal U.S. sportsbooks averaged about $14 billion in monthly wagers throughout 2025.