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Kalshi widens October lead as Polymarket’s reported share falls

CryptoBriefing reported October data showing Kalshi logged roughly 65 billion dollars in trading volume, about 10 percent higher than September, while Polymarket US recorded 10 billion dollars. Kalshi held around 83 percent share among US-regulated platforms, with open interest of about 2.05 billion dollars against 384 million dollars for Polymarket US.

CryptoBriefing’s October figures show Kalshi recording roughly $65 billion in trading volume, about 10 percent above September. Polymarket US registered $10 billion, according to the outlet’s report published Nov 1, 2026, at 10:30 AM ET.

Volume and open interest favor Kalshi

Kalshi accounted for around 83 percent of trading among US-regulated platforms, according to CryptoBriefing. That places its October volume well ahead of Polymarket US within the reported comparison.

The gap extended to open interest. CryptoBriefing put Kalshi’s outstanding positions at about $2.05 billion, compared with $384 million for Polymarket US. Those figures measure a different dimension of activity from the trading volume accumulated during the month.

CryptoBriefing’s headline also described Polymarket’s market share as falling to 27 percent. The supplied summary does not identify the denominator for that figure, so it cannot be treated as directly comparable with Kalshi’s around 83 percent share among US-regulated platforms.

What it means for prediction markets

  • Kalshi led on both reported measures: October trading volume and open interest were substantially higher than Polymarket US’s figures.
  • Market definitions matter: Polymarket’s reported 27 percent share and Kalshi’s US-regulated share should not be combined without clarification of their respective scope.
  • Platform activity is not contract-level evidence: These aggregate figures do not establish liquidity, pricing quality or outcome probabilities for individual prediction markets.
KalshiPolymarketInfiniti MarketsInfiniti Signals

Sources & attribution

Published
  1. Source
    CryptoBriefingcryptobriefing.com
    Publisher
    https://cryptobriefing.com
    Source URL
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