In this photo illustration, applications for online prediction market sites are seen on an electronic device on February 25, 2026 in Chicago, Illinois.
Scott Olson | Getty Images
FIFA 2026 World Cup it was expected that it would be the the biggest gaming event in history. For prediction market platforms, this led to a sharp rise in trading volumes in June.
Kalchi recorded more than $31 billion in notional volume during the month, an increase of more than 70% from May’s total. $17.9 billionaccording to data collected by users on Dune Analytics. The platform has consistently handled daily volume of over $1 billion since the football tournament began on June 11.
Polymarket The international event contracts exchange set a new record for monthly volume, with notional trading exceeding $10.8 billion in June. This reverses a downward trend in April and May, when volume dropped.
Meanwhile, Polymarket’s US platform generated notional volume of over $3.5 billion during the month, up from $1.77 billion in May.
Team USA MondayThe American team will face Belgium in the round of 16 on Monday evening. More than $64 million on Kalshi and $122 million on Polymarket were traded to see whether the United States would win the tournament, although the odds of that happening are only 4.3% and 3%, respectively, on each platform.
Excitement for the World Cup has given a boost to prediction market platform Rothera, a joint venture between Susquehanna International Group and Robin Hood. Rothera debuted in June, when Robinhood started deliver certain World Cup contracts on its brokerage to the platform.
Rothera recorded $2 billion in notional trading volume during the month and now represents 7% of U.S. predictive market volume, according to Bank of America.
All platforms relied on the World Cup to increase traffic. Polymarket launched a competition to reward up to $2 million to anyone who can create a perfect bracket for the World Cup Round of 16. On the Apple App Store, Kalshi boasted that users can “Trade the World Cup” in the title of its mobile platform.
Increased open interest – the total number of active and unsettled contracts on platforms – may also reflect enthusiasm for the World Cup. Kalshi’s open interest now exceeds $1 billion. Polymarket’s open interest stands at just under $400 million – a high number, but about where its international platform has been in recent months.
Last month, sports were the focus of event contract trading, but how platforms handled the increase in volume may be a sign of how they will handle other contract topics in the future.
Asaf Meir, CEO of Solidus Labs – a market integrity company which has a partnership with Kalshi – said the World Cup is a key moment for platforms such as the two regulators and institutions are interested in their performance.
Outside observers wonder: “Is it safe enough?” Is it ripe enough? Does it have enough volume? ” said Meir. “The World Cup is a huge pressure test to see if prediction markets are indeed able to keep their word on maintaining a level playing field for all investors for a long period of time, in a sustainable high volume environment.”
Disclosure: CNBC and Kalshi have a business relationship that includes customer acquisition and minority investment.
