Polymarket, Polymarket US and Kalshi monthly volume hits $50.6 billion in July

Polymarket, Polymarket US and Kalshi posted a combined monthly trading volume of $50.59 billion in July, a record in data published on Aug. 3, as FIFA World Cup betting activity drove heavy use of prediction markets. The total was up 7.8% from a revised June figure of $46.95 billion. Kalshi accounted for the largest share at $37.7 billion, or about 74.5% of the combined total, while Polymarket’s international platform fell 26% to $7.9 billion and Polymarket US rose 54% to $5 billion. Even with that gain, combined volume for Polymarket and Polymarket US slipped to $12.9 billion from about $14 billion in June. The figures reflect taker notional volume rather than exchange revenue or customer deposits, meaning they show contract turnover and liquidity rather than fresh capital entering the platforms. Trading cooled after the tournament, with open interest across the three venues dropping to about $1.2 billion at the end of July from roughly $2 billion near the start of the month. The record came as more than a dozen state regulators accused Kalshi and Polymarket of running unlicensed gambling operations and moved to block event contracts, while the platforms and the CFTC argued that federal oversight takes precedence over state rules.