[Kalshi and Polymarket's Combined Trading Volume in August Dropped 14.5% Month-on-Month, Marking the First Decline in a Year] According to data from The Block, the combined monthly trading volume of Kalshi and Polymarket fell to $45.33 billion in August, a 14.5% month-on-month decrease, marking the first monthly decline since August 2025. During the World Cup from June 11 to July 19, trading volumes in prediction markets surged significantly, but retreated in August after the event concluded. Kalshi's trading volume in August was $37.17 billion, down 7.3% month-on-month; Polymarket and its U.S. platform combined for $8.16 billion, a 36.7% month-on-month drop. However, the August trading volume still remained significantly higher than May's $25.66 billion.