Prediction market platform Kalshi added 3 million new users during the 2026 FIFA World Cup, with more than $1.2 billion traded on its contract for the tournament winner, according to figures the company gave CNBC. That single market is a record for the platform, and total World Cup volume across all Kalshi contracts topped $12 billion.
The numbers show how quickly a prediction market can scale on the back of one global event. Kalshi, which built its early business on political and economic contracts, used the tournament to pull in a mass sports audience and test whether event-driven trading can reach beyond its original base.
A marketing push built around the tournament
Kalshi did not wait for World Cup interest to reach it. The company ran an aggressive advertising campaign timed to the tournament, signing high-profile names to front its ads. Croatian midfielder Luka Modric and former Real Madrid coach José Mourinho appeared in spots, as did actor Timothée Chalamet in June and Colombian singer J Balvin in July.
The company also partnered with the Argentina national team, a tie-up that paid off when Lionel Messi posted about Kalshi on Instagram. For a platform trying to convert casual football fans into account holders, exposure to Messi’s following is the kind of reach paid media rarely buys outright.
The most important thing is enable creativity based on what’s happening.
That was how Kalshi chief executive Tarek Mansour described the approach, saying the company aimed to meet people where they already were rather than pull them onto unfamiliar ground.
The activity went beyond celebrity endorsements. Kalshi partnered with ADI Predictstreet, the official prediction market sponsor of the World Cup, to run co-branded advertising inside stadiums. It also worked with OpenAI so that its contract odds surfaced when users asked ChatGPT about tournament games, placing its prices directly inside a tool millions already use.
Why football moved the numbers
The scale of the response reflects the pull of the sport itself. Vijay Viswanathan, an associate dean for integrated marketing communications at Northwestern University, put the appeal in plain terms.
I don’t think there’s any game like football.
Football’s global reach gives a prediction market a far larger addressable audience than a US election or a corporate earnings call. The World Cup delivered a month of daily fixtures, each one a fresh trading event, which helps explain how Kalshi moved $12 billion in total volume over the tournament. The pattern of that trading also carries a warning: volume on days without matches was far lower than on match days, a sign that much of the new activity was tied to the event rather than to the platform itself.
The European backdrop
Kalshi’s tournament success lands against a tougher regulatory picture in Europe, where prediction markets remain contested. Spanish authorities moved to block Kalshi and Polymarket in a licensing crackdown, and France ordered access to Polymarket cut off, treating the contracts as unlicensed gambling rather than financial products. The debate over how to classify these platforms is shaping up as one of the defining regulatory questions for the sector, a theme explored in how prediction markets are reshaping US sports betting.
Not every jurisdiction is closing the door. Malta is weighing the first EU framework for prediction markets, which would give operators a licensed route into the bloc. The contrast with Spain’s move to block Kalshi and Polymarket shows how far European regulators are from a common line.
The retention test ahead
The immediate question for Kalshi is whether 3 million tournament sign-ups become recurring traders. Acquisition on the back of a one-off event is the easier part. Holding those users once the fixtures stop, and finding contracts that keep them trading between marquee events, is the harder problem, and the drop in off-match-day volume suggests it is already testing the platform. The 2026 World Cup gave Kalshi its largest single market to date. What it does with the audience that market delivered will show whether prediction markets can hold a mass following or simply rent one for the length of a tournament.
Source: Kalshi
