Polymarket's World Cup winner market has clocked roughly $2 billion in trading volume before a single ball is kicked, while Kalshi's parallel market crossed $100 million. The numbers underscore how deeply prediction markets have cut into traditional sports wagering ahead of the 2026 men's tournament — the first since these platforms expanded beyond crypto and politics into mainstream sports speculation.
The volume surge
It's not just World Cup-specific action. Combined monthly trading volume on Kalshi and Polymarket grew from under $5 billion in September 2025 to about $24 billion by April 2026, according to platform data. That's closing in on the roughly $14 billion monthly average that US legal sportsbooks handled in the prior year.
Sports now account for the majority of Kalshi's trades. The exchange started with political and macroeconomic contracts, but the shift happened quickly. The World Cup is the accelerant.
Why traders like these markets
Prediction markets let participants adjust positions in real time based on injuries, tactical shifts, or disciplinary news. Traditional sportsbook wagers lock in odds at the time of bet placement. That flexibility is drawing a crowd that wants to trade around events, not just pick a winner and wait.
A star player tweaks a hamstring in training? You can sell your position before the line moves. That's not something you do with a $50 futures ticket at a sportsbook.
Spain and France lead the pack
As of early June, Spain and France each carry implied winning probabilities of about 16 to 16.5 percent across both Polymarket and Kalshi. That puts them neck-and-neck at the top of the market. The tournament opens in a few weeks, and those numbers will shift with every squad announcement and warm-up match.
One thing is already clear: the 2026 World Cup is the biggest test yet for whether prediction markets can sustain sports-focused volume long after the final whistle.
