World Cup Fever Drives 300% Growth in Polymarket's Soccer Prediction Market Trading Volume, Kalshi's Open Interest Surpasses $1 Billion

BlockBeats News, June 24th. Driven by the World Cup event, the trading volume of the "Soccer" category on Polymarket exceeded $2 billion in the first 10 days after the World Cup kickoff, a 300% increase from the previous 10 days. At the same time, the average daily trading volume of this category increased from $53.1 million in the month before the opening match to around $220 million as of the current stage of the event.

Kalshi also benefited from the World Cup fever. Data shows that last Thursday, Kalshi aggregated open interest reached $1.16 billion, reaching a historic high and marking the first time the platform's open interest has exceeded $1 billion. Year-to-date, Kalshi's open interest has grown by 350%.

However, Polymarket's open interest remained relatively stable during the World Cup, with its CFTC-regulated U.S. business's open interest only showing a mild increase, failing to reach the peak in April 2026. In contrast, Kalshi's open interest growth rate outpaced its trading volume, indicating that its users have longer holding periods and are starting to show larger directional positions, rather than just engaging in short-term trading.