In this photo illustration, Applications of online betting market sites are shown on an electronic device on Feb. 25, 2026 in Chicago, Illinois.
Scott Olson | Getty Images
The 2026 FIFA World Cup was predicted to be the biggest gambling event in history. For the prediction market, that led to an increase in trading volumes in June.
Kalshi saw more than $31 billion in revenue during the month, an increase of more than 70% from May’s figure of $17.9 billion, according to user-aggregated data from Dune Analytics. The stadium has been managing a volume of more than $1 billion every day since the start of the football tournament on June 11.
Polymarket’s international event contract set a new record high for monthly volume, with estimated trade exceeding 10.8 billion in June. That reverses the decline in April and May, when volume fell.
Meanwhile, Polymarket’s US platform did north of $3.5 billion in considered volume during the month, up from $1.77 billion in May.
Team USA on Monday
Team USA will play Belgium in the round of 16 on Monday night. More than $64 million in Kalshi and $122 million in Polymarket were traded on whether the US would win the tournament, although the odds of that happening are 4.3% and 3%, respectively, in each region.
World Cup enthusiasm has provided a platform for market forecasting Rothera, a joint venture between Susquehanna International Group and Robinhood. Rothera started in June, when Robinhood started submitting certain World Cup contracts to his brokerage on the platform.
Rothera saw $2 billion in speculative trading revenue during the month, and now accounts for 7% of the US speculative market volume, according to Bank of America.
All platforms depend on the World Cup to increase traffic. Polymarket has launched a competition to award up to $2 million to whoever can build the perfect World Cup knockout bracket. In Apple’s app store, Kalshi boasted that users can “trade the World Cup” in the title of the mobile platform.
Increasing open interest – the total number of active, unfixed contracts on the pitches – could also reflect excitement for the World Cup. Kalshi’s open interest is now over $1 billion. Polymarket’s open interest is just under $400 million – raised, but about where its international platform was a few months ago.
Sports have been in the spotlight for the past month on the exchange of event contracts, but how the stadiums handle the increase in volume may be a sign of how they handle other contract topics in the future.
Asaf Meir, CEO at Solidus Labs – a market efficiency company partnering with Kalshi – said the World Cup is an important time for platforms as regulators and institutions look at how they are doing.
Outside observers are asking, “Is it safe enough? Is it mature enough? Does it have enough capacity?,” Meir said. “The World Cup is a big pressure test to see if the prediction markets are really able to deliver their voice in terms of leveling the playing field for all long-term investors in a sustained high-volume environment.”
Disclosure: CNBC and Kalshi have a commercial relationship that includes customer acquisition and a small investment.
