Prediction Market Buyers Spent $22.7 Billion in October, More Than in 2025

Prediction-market buyers paid $22.7 billion for contracts in October, exceeding the $20.9 billion spent across all of 2025 as activity expanded across trading measures.

Notional contract volume reached $123.6 billion, a 58% increase from September. The cash-paid total rose 25% over the month. This measure reflects buyers’ purchase costs; for parlays, it counts what buyers spent rather than treating each one as a $1 payout.

The number of trades rose 36% to 644 million. Fees increased 27% to $647 million, while open interest climbed 42% to $3.1 billion.

Kalshi drew 28 million site visits in October, while Polymarket drew 38 million. The earlier October figure was $123.3 billion in volume, with Kalshi accounting for about 80%.