Prediction Markets Hit Record $123.6B Notional Volume in October, a16z Says

Prediction markets registered an all-time monthly high in October 2026, generating $123.6 billion in notional trading volume, according to a report published on Nov. 5 by venture firm Andreessen Horowitz's a16z crypto ¹. The monthly total represents a 58% increase compared to prior records set in September and exceeds the combined $82 billion in notional volume recorded across all of 2024 and 2025 ¹.

Under a cash-paid measurement—which calculates contract costs rather than eventual payouts—traders deployed $22.7 billion in capital during October, representing a 25% month-over-month increase ¹. This metric also surpassed the $20.9 billion deployed across the entire year of 2025 ¹. In total, participants executed 644 million trades across platforms, up 36% from the prior month, while generating $647 million in fees and pushing open interest to $3.1 billion ¹.

Web Traffic Rivals Established News Outlets

The surge in market activity coincided with a notable shift in online attention, with platforms functioning increasingly as direct information sources ¹. Platform web traffic tracked by Similarweb showed Kalshi drawing 28 million site visits and Polymarket securing 38 million visits throughout October ¹. These traffic figures put the platforms on par with conventional media organizations, matching Bloomberg's 38 million visits and surpassing Politico's 32 million visits over the same timeframe ¹.

The figures underline expanding consumer adoption for event derivatives, continuing momentum seen as Prediction Markets Kalshi and Polymarket Face Midterms Test as Volume Surges. The elevated activity in event contracts arrives despite broader softness across digital asset markets, where $BTC traded around $75,896 and $ETH stood at $2,234 at the time of writing.