The 2026 FIFA World Cup is doing for prediction markets what March Madness does for office pools, except the stakes are measured in billions. Polymarket’s soccer category blew past $2 billion in trading volume within the first ten days of the tournament, a 300% jump compared to the equivalent period before kickoff.
Kalshi, meanwhile, crossed a milestone of its own. The platform’s aggregated open interest hit $1.16 billion last week, the first time it has ever breached the billion-dollar threshold, representing a 350% increase year-to-date.
The numbers behind the frenzy
Polymarket’s daily trading volume in the soccer category jumped from roughly $53 million to $220 million during the tournament’s opening stretch. Sports-related daily trade volumes on the platform reached over $300 million at peak, doubling from pre-tournament levels.
The flagship World Cup winner market on Polymarket alone has accumulated a lifetime trading volume between $2 billion and $3 billion. That is a single market on a single platform, handling more volume than many mid-cap crypto tokens see in a month.
