Kalshi tops $65B in October volume as Polymarket US reaches $10B
Kalshi handled about $65B in October volume, 10% above its September record, and Polymarket US about $10B, as prediction market trading kept climbing.
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Daniel Hartley
10/29/20261 min read
Kalshi has handled about $65 billion in trading volume so far in October, roughly 10% above its September record, while Polymarket US has reached around $10 billion, about 15% above its previous monthly total, according to platform figures reported by Coinpaper and TokenPost on Oct. 29. Both numbers are month-to-date and measured in notional terms, which count contracts at face value rather than the cash traders put up.
Kalshi accounted for nearly 83% of combined volume across Kalshi, Polymarket US and Polymarket's international platform, based on The Block data cited by Coinpaper. The two US-regulated venues together took 95.6% of activity. Open interest stood at $2.05 billion on Kalshi and $384 million on Polymarket US.
The growth has been steep. A year ago, Kalshi's October volume was about $4.4 billion, roughly level with Polymarket's international exchange. This month, Kalshi's volume was 18.7 times that of Polymarket Global. The Block's prediction-to-spot ratio climbed to 11.42 in October from 7.34 in September, though Coinpaper cautioned that the measure is specific to its dataset and does not compare dollar volumes directly.
Brokers follow the flow
The shift is visible in broker earnings. Robinhood reported $173 million of prediction-market revenue in the third quarter, more than the $120 million it earned from crypto trading. Coinbase said on Oct. 29 that its prediction-market business, launched in February, had passed $200 million in annualised revenue.
The reported totals do not separate election contracts from sports, crypto and other markets, so it is unclear how much of the October increase is tied to the approaching US midterm elections, TokenPost noted. Polymarket's US expansion rests on its $112 million acquisition of CFTC-licensed exchange QCEX.
The record month comes against a turbulent backdrop for the sector. Polymarket suspended international trading on Thursday after hackers drained more than $2.6 million from user accounts, CoinDesk reported. Final October figures will be available after the month closes on Oct. 31.
Source: Coinpaper, TokenPost, The Block, CoinDesk