Kalshi and Polymarket Volume Drops 15% in August
First monthly volume decline in a year hits prediction markets as post-election momentum fades
Prediction market volumes at Kalshi and Polymarket dropped 15% in August 2026, marking the first monthly decline in a year, according to The Block.
Why It Matters
The pullback signals that the explosive post-election growth cycle that turbocharged prediction markets through late 2025 and early 2026 may be losing momentum. Kalshi posted $37.17 billion in August volume — still a substantial figure — while Polymarket and its US platform combined for $8.16 billion, per The Block. For bettors and traders, thinner volume typically means wider spreads and reduced liquidity on longer-tail contracts. Operators will face pressure to introduce new contract categories or improve market-maker incentives to reverse the trend.
Context
Prediction markets surged into mainstream financial discourse following the 2024 US election cycle, with both Kalshi — which holds CFTC authorization — and Polymarket attracting institutional and retail capital at a pace that made monthly volume records routine. As of September 2026, the combined August total still represents significant scale, but the year-over-year comparison will grow harder to flatter as the prior period's politically driven spikes roll into the base. Gambling always carries risk, and prediction market participants should treat volume figures as a liquidity signal, not a performance guarantee.
What's Next
The next inflection point will likely come from the November 2026 US midterm election cycle, which historically drives outsized contract creation and trading activity on both platforms. Watch whether September volumes recover or extend the August decline before that catalyst arrives.
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