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Kalshi and Polymarket monthly volume falls 14% to $45B in August as World Cup hangover sets in
The prediction market boom isn't over, but August's numbers show what happens when the biggest sporting event on earth stops generating contracts.
Combined trading volume across Kalshi and Polymarket dropped 14.5% in August to $45.33 billion, marking the first meaningful pullback after months of relentless growth in the prediction markets sector.
The decline follows a record-setting July that saw $50.59 billion in combined volume across the platforms. That peak had a very specific catalyst: the FIFA World Cup, which ran from June 11 to July 19 and turbocharged sports betting contracts across both platforms.
The World Cup effect, in reverse
July’s $50.59 billion represented a 7.8% jump from June’s revised figure of $46.95 billion.
Sports contracts have accounted for over 88% of recent activity on Kalshi. Kalshi maintained 85-90% of its comparable weekly volume heading into late August, while Polymarket’s offshore platform saw a steeper contraction.
In July, Kalshi contributed $37.7 billion in volume, roughly 74.5% of the combined total across both platforms.
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NFL steps up, but can’t fill the gap
NFL preseason markets generated $167.8 million across Kalshi, Polymarket Global, and Polymarket US in the week ending August 16. Kalshi handled approximately 79% of that activity.
Kalshi also posted a notable milestone despite the broader downturn. For the week ending August 30, the platform’s weekly contract volume exceeded $10 billion for the first time, hitting $10.17 billion.
Different platforms, different audiences
Kalshi, operating as a CFTC-regulated exchange in the US, has leaned heavily into sports. Polymarket Global, meanwhile, has attracted more interest in macro and esports markets.