World Cup Ignites Prediction Markets: Polymarket Trading Volume Surges 300%, Kalshi Open Interest Hits Record $1.16 Billion

According to Odaily, within the ten days leading up to the World Cup, Polymarket's football category trading volume exceeded $2 billion, a 300% increase compared to the prior ten-day period. Daily average trading volume rose from $53 million before the tournament to approximately $220 million. Meanwhile, Kalshi's open interest reached a record $1.16 billion last Thursday, breaking the $1 billion mark for the first time and growing 350% year-to-date.

Although Polymarket's open interest remained relatively stable during the World Cup, and its U.S. branch only saw modest growth without reaching its April 2026 highs, Kalshi's open interest grew faster than its trading volume. This indicates that its user base holds positions for longer periods and has established larger directional positions. Kalshi's CFTC-regulated channels and direct USD deposit options have attracted U.S. institutions and high-net-worth dollar investors. (The Block)