TLDR Kalshi and Polymarket combined for $50.59 billion in trading volume in July, a new record. Kalshi processed $37.7 billion in trades, up 14% from June. Polymarket’s offshore platform dropped 26% to $7.9 billion, while Polymarket US grew 54% to $5 billion. The World Cup final between Spain and Argentina drew about $1.9 billion on Kalshi and $4 billion on Polymarket for the tournament winner market. Open interest fell from about $2 billion to $1.2 billion after the tournament ended, and legal fights with state regulators continue.
Prediction markets set a new record in July. Kalshi and Polymarket together generated $50.59 billion in trading volume, the highest monthly total either platform has seen.
The jump came mostly from betting tied to the FIFA World Cup. Once the tournament ended, trading activity slowed down fast.
Kalshi led the growth. The platform processed $37.7 billion in trades during July, a 14% increase from June.
That growth kept Kalshi ahead of its main rival. Polymarket’s results were more mixed across its two platforms.
U.S. Trading Shifts Toward Polymarket US
Polymarket’s offshore platform saw trading volume fall 26% month over month, down to $7.9 billion. At the same time, its U.S. platform moved in the opposite direction.
Polymarket US grew 54% to $5 billion in July. The growth came after the company removed its waitlist in May, opening the platform to all eligible American users.
Combined, both Polymarket platforms brought in $12.9 billion. That is down from roughly $14 billion in June.
The shift points to American users moving away from the offshore site. Polymarket US operates under oversight from the Commodity Futures Trading Commission, giving U.S. traders a regulated option.
Rutgers University statistician Harry Crane had estimated earlier this year that U.S. users made up about 30% of trading volume