Woofun AI data shows Kalshi’s June trading volume reached nearly $9.4 billion, establishing a new historical high compared to approximately $5.3 billion in May. Polymarket International also saw growth, rising from roughly $3.5 billion to $4.3 billion during the same period.

The 2026 FIFA World Cup, expanding to 48 teams, served as the primary catalyst for this surge. Knockout stage activity was intense, with the Canada-Morocco Round of 16 match generating over $48 million on Kalshi and $26.8 million on Polymarket.

Concurrently, regulatory challenges persist: nearly a dozen US states have taken action against these platforms, prompting CFTC Chairman Selig to condemn such enforcement as illegal. In Europe, ESMA warned that many event contracts may fall under existing binary options restrictions.