Spain Won the 2026 FIFA World Cup, But Kalshi Won the Betting War

^{Fans at the 2026 FIFA World Cup final match between Spain and Argentina in East Rutherford, New Jersey. (Photo: CNSphoto / Alamy)} 

The 2026 FIFA Cup has come to a close, with Spain defeating Argentina 1-0 in the final on July 19. Though Spain won the trophy, prediction market platform Kalshi also celebrated a big win over traditional sportsbooks.

Kalshi added 3 million new users over the course of the tournament, the prediction market platform confirmed to CNBC. The contract on the winning team in the World Cup final generated more than $1.2 billion in trading volume, setting a record for any single market on the platform. Prediction markets captured about 27% of the legal U.S. World Cup betting volume, tripling their share from the beginning of 2026.

Kalshi consistently saw daily trade volumes of over $1 billion since the tournament began on June 11. The platform saw a total of over $31 billion in total trading volume during June, which is more than 70% than in May. By comparison, analysts had expected U.S. sportsbooks to take in somewhere between $2.8 billion and $4.3 billion across all 104 matches.

The platform even managed to outpace sports betting giants DraftKings and FanDuel in daily app users during the tournament.

What Prediction Markets Can Do That Sportsbooks Can’t

Prediction markets differ from sportsbooks in the way they work, which is essential to understanding how they made bank during the World Cup. On a prediction market platform like Kalshi or Polymarket, you're trading contracts against users rather than betting against the house (like in sportsbooks). Users wager on the likelihood of real-world outcomes, and the platform makes money by charging small fees on every transaction rather than collecting losses.

That also means Kalshi doesn't ban big winners or successful bettors from the platform, unlike a traditional casino sportsbook might. 

Prediction markets allow for trading on a variety of outcomes, including sports, entertainment, elections, weather patterns, and even economics. But sports betting continues to dominate as the top category on Kalshi, and the World Cup demonstrated that in spades. 

Kalshi is regulated by the Commodity Futures Trading Commission (CFTC). States argue that they have the right to regulate sports betting, while the CFTC maintains that Kalshi is offering contracts that fall within its regulatory authority.

That argument has played out in ongoing legal battles in several states and has even drawn congressional scrutiny. An appeals court previously ruled in Kalshi's favor on election contracts, bolstering the platform's federal-only jurisdiction argument.

States have pushed back regardless. Nevada's gaming regulators issued a cease and desist order against Kalshi, restricting users from trading on sports and entertainment markets, even during the World Cup. Other states like Michigan, New Mexico, and Massachusetts have taken legal action against Kalshi’s sports prediction contracts in their jurisdictions . 

Kalshi Doubles Down on Ads

Kalshi's widespread growth is partly thanks to its partnership with ADI Predictstreet, the official prediction market sponsor of the 2026 FIFA World Cup. The partnership gave Kalshi branding opportunities at stadiums, on TV, and online throughout the tournament. Kalshi also partnered with OpenAI to display contract odds when people searched for match information on ChatGPT. 

The celebrity campaign in the ads was hard to miss as a viewer. Kalshi struck a second partnership with the Asociación del Fútbol Argentino, Argentina's national football governing body, which included a social media post featuring Lionel Messi promoting the platform. Croatian soccer star Luka Modrić and Colombian singer J Balvin showed up in Kalshi’s ads during the tournament. 

Timothée Chalamet appeared in June, timed to his high-profile appearances at New York Knicks games during the NBA Finals. The "Dentist" commercial he appeared in did extremely well, generating 796 times more engagement than any other ads in the World Cup, according to advertising analytics firm EDO.

The single ad outperformed other commercials from other brands that ran during the tournament, such as Adidas and Coca-Cola. Kalshi CEO Tarek Mansour told CNBC that one commercial featuring former pro soccer players playing a scrimmage was produced and released within a single day.

Next Challenge: Retaining New Users

Mansour has acknowledged that the challenge after such a successful event is converting those new users into repeat users who consistently engage with the app. Trade volume on days without World Cup matches was lower compared to match days during the tournament, so it’s not surprising that it would be an ongoing challenge after the tournament concluded. 

In interviews with CNBC, Mansour pointed to politics, economics, and weather markets as the categories that bridge the gap to keep users engaged between sporting events. The platform's growth during elections has been well documented since its breakout moment during the 2024 presidential election. The World Cup appears to have introduced Kalshi to an entirely new demographic of sports bettors who had never engaged with prediction markets before. 

Traditional sportsbooks may have had some competition, but they weren’t totally shut out. The U.S.'s loss to Belgium set records for the country’s betting operators and became the most-bet soccer match in the history of many major sportsbooks. 

Prediction markets like Kalshi or Polymarket are no longer as niche as they used to be. These platforms have jumped from representing just 9% of U.S. sports betting at the beginning of 2026 to 27% during the World Cup. Their convenience may lead people to favor them over traditional sportsbooks down the line as they become even more popular.