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October trading records highlight sports dominance in prediction markets

Jefferies analyst Dan Fannon put October open interest at a record 3.27 billion dollars, up 45 percent from September, with sports contracts at 83 percent of open interest. Polymarket average daily volume rose 50 percent to 655 million dollars, up 395 percent from October 2025.

Prediction markets reached a record $4.13 billion in average daily trading volume in October, an increase of 55 percent, according to CardPlayer. Sports accounted for $3 billion of that daily activity.

Sports lead trading and open positions

Jefferies analyst Dan Fannon put October open interest at a record $3.27 billion, up 45 percent from September, according to CardPlayer. The increase accompanied the new high in daily trading volume.

Sports contracts represented 83 percent of open interest. That concentration placed sports at the center of both trading activity and outstanding positions, although the two measures capture different aspects of market participation.

Polymarket posts substantial growth

Polymarket’s average daily volume increased 50 percent to $655 million, according to CardPlayer. Compared with October 2025, its average daily volume was up 395 percent.

The figures show growth across both the overall prediction-market totals and Polymarket’s activity. They also distinguish a market-wide record in open interest from the platform’s reported gains in daily turnover.

What it means for prediction markets

  • Sports concentration matters: With sports accounting for $3 billion in daily volume and 83 percent of open interest, aggregate activity is heavily weighted toward those contracts.
  • Volume and open interest offer different signals: Record daily turnover measures trading activity, while the $3.27 billion open-interest figure tracks outstanding positions.
  • Platform growth is not the same as market-wide growth: Polymarket’s 50 percent increase in daily volume and 395 percent rise from October 2025 should be distinguished from the overall market’s 55 percent increase.
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