Key Takeaways
- Kalshi, Polymarket, and Polymarket U.S. traded a combined $44.8B in June, up 75% from May’s $25.66B.
- Kalshi took the largest share at $31.5B, roughly 70% of the total, growing 87% month over month.
- Trading volume is not money staked – contracts are resold repeatedly, so the figure overstates funds at risk.
The World Cup-induced growth spurt continues
Kalshi, combined with Polymarket’s international platform and its U.S.-regulated exchange, recorded a combined $44.8 billion in monthly trading volume in June. This marks a 75% jump from May’s $25.66 billion, according to The Block’s data dashboard. Kalshi drove most of the increase, growing 87% month over month to $31.5 billion.
The main cause of the growth is the FIFA World Cup co-hosted by the U.S., which began on June 11 and quickly became the largest liquidity event the sector has seen. Kalshi alone processed about $7.4 billion in World Cup trades during the tournament so far – more than its entire March Madness volume – while Polymarket’s event markets drew roughly $6.4 billion, demonstrating that they can absorb sustained trading around one recurring subject.
Prediction-market volume had climbed steadily earlier in 2026 — combined monthly totals were around $25.7 billion in March and $25.66 billion in May, per earlier tracking – so June’s $44.8 billion marks a tournament-driven step change rather than a departure from the trend. Whether that level holds once the World Cup ends is the open question; June was as much a test of event-driven demand as a durable record, and while the tournament is only just approaching its business end, the elimination of the USMNT will inevitably impact fan interest.
Some trackers put June’s total above $50 billion; that figure, using Artemis data, counts additional venues such as the Robinhood-backed Rothera alongside Kalshi and Polymarket, whereas The Block’s $44.8 billion covers the two dominant platforms and Polymarket US – the two measure different venue sets rather than contradicting each other. A separate $50 billion figure has also circulated: Macquarie’s pre-tournament forecast for the total World Cup wagering across the whole event, which is a projection of all betting activity over roughly six weeks — not a measure of monthly prediction-market trading volume, and not directly comparable to it.
It is also worth keeping in mind that volume is not the same as money wagered. Prediction-market contracts are bought and sold repeatedly before a market settles, so a single dollar can change hands many times and be counted at each step – meaning the headline volume overstates the amount actually staked on outcomes.
For comparison, Pew Research Center has noted that U.S. legal sportsbooks handled around $14 billion per month in wagers in 2025, a figure that measures money bet rather than contracts traded, and is not directly comparable to prediction-market volume for that reason.
Whether June’s level marks a durable shift or just a World Cup spike is the key question of the coming months. For sports fans, there is always going to be something to follow and trade on.
