Kalshi picked up 3 million new users during the 2026 FIFA World Cup, the company said, as trading on its winner-take-all contract for the tournament hit a record $1.2 billion. Spain beat Argentina 1-0 in the final, settling the biggest single-market wager in the platform's history.
The World Cup Betting Boom
Kalshi's growth spurt didn't happen by accident. The exchange partnered with ADI Predictstreet, FIFA's official prediction market sponsor, for stadium co-branding. It also worked with OpenAI to surface its odds inside ChatGPT searches. Campaigns featured soccer stars Luka Modric and Jose Mourinho, plus a partnership with the Argentina national team.
CEO Tarek Mansour said the strategy prioritizes speed and relevance over volume alone. The numbers back him up: the $1.2 billion traded on the World Cup winner contract dwarfed anything Kalshi had seen before on a single market.
Regulatory Crossfire
Sports event contracts remain in dispute between the federal government and several states. The Commodity Futures Trading Commission filed a lawsuit against Kentucky this year over the legality of such markets. Brian Sung, a partner at law firm Haynes Boone, said the marketing push does not sway how courts might rule but shapes how regulators and the public view prediction markets.
One Polymarket trader lost $11.6 million on World Cup wagers in early July, a reminder that these markets carry real financial risk.
Volume drops on days without matches, Mansour acknowledged. He expects fresh catalysts — likely the next major sports event or a new contract type — to keep volume climbing after the World Cup. The company now faces the challenge of retaining those 3 million new users while navigating a patchwork of state and federal rules.
