Kalshi and Polymarket see their combined trading volumes decline 15% in August, marking the first monthly drop in about a year, according to reporting based on the exchanges’ monthly totals. In August, Kalshi records $37.17 billion in volume, while Polymarket and its US-facing platform together account for $8.16 billion.
The figures indicate a slowdown in overall activity across both prediction-market platforms during the month. The outlets align on the direction and magnitude of the change—down 15%—and on the specific volume totals for Kalshi and Polymarket. Differences in coverage are limited, as both sources focus primarily on the aggregate performance and the year-long pattern implied by the first decline.
