Hassan Maishera
TL;DR
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Kalshi, Polymarket, and Polymarket US recorded a combined $50.59 billion in trading volume in July, a new monthly record.
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Kalshi led the market with $37.7 billion in volume, growing 14% month-over-month.
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The FIFA World Cup fueled trading activity, with billions wagered on tournament outcomes across prediction markets.
Prediction market platforms Kalshi, Polymarket, and Polymarket US recorded a combined $50.59 billion in trading volume during July, setting a new monthly record as betting activity surged around the FIFA World Cup.
According to data from The Block, the combined monthly trading volume increased 7.8% from $46.95 billion in June, highlighting continued growth in the prediction market sector.
Kalshi Extends Market Lead
Kalshi remained the industry's largest prediction market platform in July, generating $37.7 billion in monthly trading volume.
The figure represents a 14% increase from June, further widening Kalshi's lead over its competitors.
Meanwhile, trading activity shifted between Polymarket's global platform and its U.S.-focused counterpart.
Polymarket's offshore platform recorded $7.9 billion in monthly volume, a 26% decline from the previous month. In contrast, Polymarket US posted $5 billion in trading volume, reflecting a 54% month-over-month increase.
Although the combined volume across Polymarket's two platforms slipped from $14 billion in June to $12.9 billion in July, the data suggests that trading activity migrated toward the regulated U.S. platform.
Polymarket US, which operates under the oversight of the Commodity Futures Trading Commission (CFTC), expanded access in May by removing its initial waitlist and opening the platform to all eligible U.S. users.
The broader rollout enabled American traders who had previously accessed the offshore platform through workarounds to trade on the regulated platform instead.
Earlier this year, Rutgers University statistician Harry Crane estimated that U.S.-based traders accounted for roughly 30% of the offshore Polymarket platform's trading volume during the 12 months ending April 30, 2026.
World Cup Drives Billions in Prediction Market Bets
The record-breaking July trading activity was largely fueled by the FIFA World Cup, which ran from June 11 to July 19.
Kalshi's market for the tournament's final match between Spain and Argentina generated approximately $1.9 billion in trading volume.
On Polymarket, the contract predicting the eventual World Cup champion attracted nearly $4 billion in wagers, underscoring the tournament's role in driving user engagement across prediction markets.
Despite July's record trading volumes, market participation cooled once the World Cup concluded.
Combined open interest across Kalshi, Polymarket, and Polymarket US fell from around $2 billion at the beginning of July to approximately $1.2 billion by the end of the month, indicating that traders closed out positions after the tournament wrapped up.
Prediction Markets Continue to Face Regulatory Pressure
While prediction markets continue to gain popularity and attract higher trading volumes, the industry remains under legal scrutiny in the United States.
More than a dozen state regulators have accused Kalshi and Polymarket of offering unlicensed gambling products through their sports-related event contracts and have sought to block the platforms' operations within their jurisdictions.
Kalshi and Polymarket, together with the CFTC, have challenged those enforcement efforts, arguing that federally regulated event contracts fall under federal oversight and therefore preempt state regulatory authority.
