For the first time, Kalshi and Polymarket's combined trading volume fell to $45.33 billion in August, marking their first monthly decline.

According to Odaily Planet Daily, the combined monthly trading volume of Kalshi and Polymarket fell to $45.33 billion in August, a 14.5% decrease month-over-month, marking the first monthly decline since August 2025. Trading volume in the prediction market rose during the World Cup from June 11 to July 19, but declined in August after the tournament ended. Kalshi's August trading volume was $37.17 billion, a 7.3% decrease month-over-month; Polymarket and its US platform's combined trading volume was $8.16 billion, a 36.7% decrease month-over-month. August's trading volume was higher than May's $25.66 billion.