[October Prediction Market Trading Volume Reaches $123.3 Billion, Kalshi Accounts for Approximately 80%] October's total prediction market trading volume reached $123.3 billion, surpassing $100 billion for the first time, representing a 53.9% increase from September, with 642.9 million transactions. Kalshi accounted for $98.2 billion of this volume, approximately 80%, with 465.5 million transactions; Polymarket accounted for $20.2 billion, with 148 million transactions. Combination bets for the US football season accounted for 67.6% of Kalshi's monthly trading volume, with most contracts priced below 1 cent. Kalshi counts its trading volume based on a full redemption value of $1 per contract. Trading volume in the US midterm election market exceeded $1.4 billion, and Kalshi and Polymarket cryptocurrency contract trading volumes surpassed $3 billion for the first time in two consecutive weeks. Polymarket's US platform saw trading volume approach $10 billion in October, a 15% increase from previous records.