Prediction Markets Kalshi and Polymarket Hit Record $50.59 Billion Trading Volume in July 2026

Prediction markets Kalshi, Polymarket, and Polymarket US achieved a record combined trading volume of $50.59 billion in July 2026, representing a 7.8% monthly increase. This surge was heavily driven by the FIFA World Cup, with Kalshi's final match market alone drawing $1.89 billion. However, open interest fell from $2 billion to $1.2 billion by month-end as the tournament concluded. Amid this growth, the platforms face intensifying legal battles, including a lawsuit from New York and regulatory challenges from over 10 states.

Record prediction market volume

• ▪The $50.59 billion July 2026 figure measures taker notional volume, which reflects contract turnover and liquidity rather than platform income or customer deposits
• ▪Combined monthly trading volume for Kalshi, Polymarket, and Polymarket US reached a record $50.59 billion in July 2026, representing a 7.8% increase from the revised June 2026 total of $46.95 billion

Platform market share trends

• ▪Combined volume for Polymarket's international and U.S. platforms fell to $12.9 billion in July 2026 from approximately $14 billion in June 2026
• ▪Kalshi recorded $37.7 billion in trading volume in July 2026, a 14% increase from June 2026, representing approximately 74.5% of the three platforms' combined total

Polymarket US growth surge

• ▪Polymarket US trading volume increased 54% to $5 billion in July 2026, while Polymarket's international platform volume declined 26% to $7.9 billion
• ▪Polymarket US expanded access to eligible U.S. users after removing its initial application waitlist in May 2026

World Cup trading spike

• ▪Polymarket's market on the FIFA World Cup winner attracted approximately $4 billion in trading volume during the tournament
• ▪Kalshi's market on the FIFA World Cup final between Spain and Argentina recorded approximately $1.89 billion in trading volume

Post-tournament activity decline

• ▪The decline in open interest to $1.2 billion signaled weaker post-tournament activity as World Cup positions settled or closed
• ▪Open interest across Kalshi, Polymarket, and Polymarket US fell from approximately $2 billion at the start of July 2026 to around $1.2 billion by the end of the month

State regulatory litigation battles

• ▪More than 10 state governments have taken action against Kalshi and Polymarket, arguing that their sports contracts violate state gambling laws
• ▪A Minnesota federal judge temporarily blocked the state from enforcing its prediction-market law against Kalshi and Polymarket US on July 27, 2026
• ▪New York sued Kalshi on July 31, 2026, alleging the platform operates an unlicensed gambling operation and seeking fines, forfeiture, and customer restitution