After Spain won the 2026 final, Kalshi @Kalshi and Polymarket @Polymarket showed how prediction markets can turn major sports events into large-scale trading activity. CNBC reported that Kalshi added 3 million new users during the World Cup. The company also said more than $1.2B was traded on its World Cup winner market, making it the largest single market in Kalshi’s history. Earlier in the tournament, CNBC reported that Kalshi reached more than $31B in June notional volume, up more than 70% from May, with sports contracts accounting for roughly 85% of activity. Apptopia reported that Kalshi and Polymarket together held 73.5% of betting-market app downloads in the first half of June. The World Cup put prediction markets in front of a mainstream sports audience.