- Kalshi, Polymarket and Polymarket US reached a record $50.59B in July trading volume, up 7.8% from the revised June total.
- FIFA World Cup prediction markets fueled July activity, with Kalshi handling $37.7B and Polymarket US posting 54% monthly growth.
- Record prediction market trading came as Kalshi and Polymarket continued fighting state legal challenges over sports event contracts.
Kalshi, Polymarket, and Polymarket US recorded a combined $50.59 billion in July trading volume, the highest monthly total on record, according to data published Aug. 3. The record followed heavy prediction market activity during the FIFA World Cup, although the figures represent contract trading volume rather than deposits or platform revenue. July’s combined total also increased 7.8% from the revised June volume of $46.95 billion.
World Cup Drives Trading Activity
Kalshi remained the largest platform during July, generating $37.7 billion in monthly volume. That represented roughly 74.5% of the combined total and marked a 14% increase from June.
Meanwhile, Polymarket’s platforms moved in opposite directions. Polymarket US recorded the strongest monthly growth, with volume climbing 54% to $5 billion. However, Polymarket’s international platform fell 26% to $7.9 billion. As a result, their combined monthly volume declined from $14 billion to $12.9 billion.
According to the data, the FIFA World Cup contributed heavily to July’s activity. The tournament ran from June 11 through July 19. Kalshi’s Spain-Argentina final market generated about $1.9 billion, while Polymarket’s World Cup winner market attracted roughly $4 billion.
U.S. Platform Expands Access
The volume shift followed Polymarket US removing its waitlist in May. The Commodity Futures Trading Commission-regulated platform then became available to all eligible U.S. users.
Earlier this year, Rutgers University statistician Harry Crane estimated that about 30% of Polymarket’s offshore volume came from U.S. traders during the previous 12 months. However, he also noted blockchain transactions cannot directly identify user locations.
Notably, open interest across the three platforms dropped from about $2 billion at the beginning of July to roughly $1.2 billion by month-end as World Cup contracts settled.
Legal Challenges Continue
Despite the record trading volume, regulatory disputes remain active. More than a dozen state regulators have accused Kalshi and Polymarket of operating unlicensed gambling platforms through sports-related contracts.
However, the companies and the CFTC continue challenging those enforcement actions, arguing that federal oversight takes precedence over state jurisdiction. Separately, New York filed suit against Kalshi on July 31, while a Minnesota federal judge temporarily blocked state enforcement against Kalshi and Polymarket US during an ongoing legal dispute.
