Prediction Markets Hit $12.2 Billion in Weekly Volume as World Cup Drives Unprecedented Sports Betting Activity

Prediction markets have never been bigger. The week ending June 15 produced back-to-back all-time highs across every major sector metric — trading volume, open interest, daily fees, and active users — as the FIFA World Cup sent an enormous wave of sports betting activity through platforms like Kalshi and Polymarket.

Weekly notional volume reached $12.2 billion, according to data published by venture capital firm a16z crypto. Sports-related contracts accounted for $5.8 billion of that total — nearly half — with World Cup match markets representing the single largest driver of activity. The tournament, which is being played across the United States, Canada, and Mexico, has introduced a new category of casual bettor to the prediction market format, converting one-time sports fans into returning platform users.

Record Open Interest Signals a Structural Shift

Open interest reached $1.48 billion during the same week, a sixfold increase over the prior 12 months. Unlike trading volume, which measures total transaction flow, open interest reflects how much capital remains committed and at risk in unresolved contracts. That sixfold expansion in a single year suggests the growth is not just transactional volume — users are holding longer-duration positions and treating prediction markets as a genuine financial instrument rather than a one-off bet.

Weekly fees hit a record $76.8 million and active users reached 426,975, both all-time highs for the sector. Kalshi and Polymarket account for the majority of industry activity, with smaller platforms trailing significantly. The concentration at the top reflects a market that is still maturing even as it scales rapidly.

What It Means for the Sports Betting Landscape

The World Cup’s impact on prediction markets offers a window into what the sector can look like when a major sustained event runs for weeks and creates new markets on a daily basis. The format differs from traditional sports betting in meaningful ways — binary contracts, event-driven pricing, and markets that extend well beyond game outcomes to cover player statistics, group standings, and tournament advancement. For sports bettors already accustomed to using sportsbook promotions, prediction markets offer a complementary set of tools.

The growth has not gone unnoticed by regulators. More than 41 state attorneys general have argued to the Commodity Futures Trading Commission that sports prediction markets are effectively unregulated sportsbooks, and a multi-state legal battle over jurisdiction is actively playing out. DraftKings and FanDuel both launched prediction market products to compete with Kalshi but have faced regulatory pushback in states that consider their offerings unauthorized gambling.

For sports bettors who want to track the World Cup on prediction markets, the record volume suggests liquidity is not a concern. The futures market equivalent on traditional sportsbooks covers similar ground — outright winners, group progression, and individual statistical milestones — but prediction markets have emerged as a genuine complement to those offerings, particularly for markets that traditional sportsbooks don’t price at all.