World Cup Sparks Prediction Market: Polymarket Trading Volume Up 300%, Kalshi Open Interest Hits Record $1.16 Billion

According to Odaily, within the ten days leading up to the World Cup, Polymarket's soccer category trading volume exceeded $2 billion, a 300% increase compared to the previous ten days. The average daily trading volume rose from $53 million before the tournament to approximately $220 million. Meanwhile, last Thursday, Kalshi's open interest reached a record $1.16 billion, surpassing the $1 billion mark for the first time and growing 350% since the beginning of the year.

Although Polymarket's open interest levels remained relatively stable during the World Cup, the open interest on Polymarket's U.S. branch only saw moderate growth, failing to reach the highs from April 2026. Kalshi's open interest has grown faster than its trading volume, indicating that its user base holds positions for longer periods and has established larger directional positions. Its CFTC-regulated channel and direct USD deposit gateway have attracted U.S. institutions and high-net-worth dollar investors. (The Block)