Kalshi Sets June Trading Volume Record as World Cup Boosts Forecast Markets

Prediction markets logged a striking surge in June, and the catalyst was unmistakable: the 2026 FIFA World Cup. According to DefiLlama, Kalshi processed nearly $9.4 billion in trading volume during the month, compared with about $5.3 billion in May. Polymarket International also rose to roughly $4.3 billion from approximately $3.5 billion the previous month.

The tournament began on June 11 and is the first FIFA World Cup to expand to 48 teams. Earlier coverage from CNBC reported that the competition became the biggest driver of prediction market activity in June, citing Dune Analytics data showing record notional volumes on both Kalshi and Polymarket.

Key takeaways

• Kalshi’s June trading volume nearly reached $9.4B, up from about $5.3B in May, with the World Cup serving as the primary driver.
• Polymarket International climbed to about $4.3B in June from roughly $3.5B in May, mirroring broader interest in football-related contracts.
• World Cup Round-of-16 matchups showed especially heavy participation, with some markets generating tens of millions in volume.
• The growth in trading volume is occurring alongside intensifying U.S. legal and regulatory pressure on prediction markets.

World Cup expansion meets prediction market demand

Football has long been a natural fit for markets where participants want to express views on outcomes. But this year’s tournament offers a larger menu of games and implications. With the World Cup expanding to 48 teams—up from 32 in previous editions—the number of match results, advancement scenarios, and related questions naturally multiplies, giving traders more opportunities to place event-linked bets.

CNBC’s reporting, referenced in the source, framed the World Cup as the dominant driver of June activity. It tied the surge to Dune Analytics figures indicating record notional trading volumes on both platforms, aligning with the month-over-month jump visible in DefiLlama’s protocol-level data.

Round-of-16 matchups pull in the highest volume

As the tournament moved into the knockout stage, trading activity concentrated further around high-stakes fixtures. One example highlighted in the source was Canada’s Round of 16 match against Morocco, scheduled for Saturday. At the time of writing, the match had generated over $48 million in trading volume on Kalshi and over $26.8 million on Polymarket.

Other advancement markets also attracted notable attention in the U.S. Round of 16 matchup. The source states that on Kalshi, a market on which team would advance generated more than $2.1 million in volume as of Saturday. On Polymarket, a comparable market had pulled in around $1.6 million by the same time.

For market participants, these figures underline a practical point: the World Cup doesn’t just bring overall volume—it can also concentrate liquidity into specific, time-sensitive contracts where traders rush to price developments and adjust their expectations as lineups, tactical decisions, and match conditions become clearer.

Trading growth collides with expanding legal pressure in the U.S.

Even as competition-linked volumes climb, prediction markets in the United States remain mired in a rapidly evolving legal debate. The source notes that by March, nearly a dozen U.S. states had taken action against companies including Kalshi and Polymarket. Some states aimed to halt prediction markets, while others sought to bring them under existing gambling laws and state tax frameworks.

Federal regulators have pushed back. The source points to a statement from CFTC Chair Michael Selig, referenced via a CFTC press release, who accused states of pursuing “illegal enforcement actions” against federally regulated exchanges. Selig argued that Congress gave the CFTC sole authority over commodity derivatives markets, which would include prediction markets, warning: “To any state that seeks to nullify federal law and seize authority over these markets, we will see you in court.”

The disagreement has also moved beyond agencies and into the broader legislative arena. In June, casino operators, tribal organizations, and labor groups urged Congress to carve sports-event contracts out of the CFTC’s authority through an amendment to the Digital Asset Market Clarity (CLARITY) Act—arguing those contracts should remain governed by state gambling laws and existing gaming oversight.

Regulators overseas: product substance, not labels

While the U.S. fight has centered on regulatory jurisdiction and enforcement, Europe has emphasized how products are categorized. The source cites an ESMA reminder issued on Friday that many event contracts may already fall under existing restrictions tied to binary options.

Crucially, ESMA’s position—as presented in the source—is that whether a product is regulated depends on its characteristics rather than the presence of an “event contract” label. That means platforms and market operators face a compliance challenge that is less about terminology and more about how specific contract mechanics are structured.

For traders and builders, the key question now is whether the World Cup-driven volume spike will translate into sustained engagement once the tournament ends—or whether liquidity fades as the legal and regulatory backdrop remains unresolved. Readers should watch for further court activity and potential legislative movement around CLARITY, since those outcomes could materially shape what kinds of contracts are allowed, where, and under what rules.