Prediction markets recorded a weekly trading-volume record of $20.4 billion, the first time the sector has exceeded $20 billion, according to Artemis data. The previous week reached $19.8 billion. The past two weeks also surpassed the sector’s earlier peak during the FIFA World Cup in June and July. Weekend activity set daily records, with total volume reaching $4 billion across Saturday and Sunday; Kalshi handled around $3 billion on each day. Kalshi accounted for about 77% of last week’s tracked volume, or $15.8 billion, ahead of Polymarket at $3.6 billion, Nadex at $481.9 million and Rothera at $272.3 million. Predict.fun and Opinion each exceeded $120 million. Polymarket recorded $770.4 million on Saturday and $662.4 million on Sunday, but Kalshi’s faster growth through September has created the widest gap between the platforms this year. Monthly volume had already surpassed July’s previous high as the NFL and U.S. college football seasons began, concentrating sports trading on weekends. Parlay-style contracts, which combine multiple outcomes into one payout, can inflate headline volume because Kalshi counts contracts at their $1 payout value rather than their purchase price. A $20 wager on a parlay priced at 5 cents represents 400 contracts and $400 in reported volume, despite only $20 being at risk. The Federal Reserve’s September rate decision, short-duration crypto markets tied to Bitcoin and Ether price closes, and early positioning for the Nov. 3 U.S. midterm elections also contributed. The elections are five weeks away, with control of both chambers of Congress at stake, while the NFL regular season runs into early January.