Prediction markets recorded a weekly trading volume of $20.4 billion, marking the first time the sector has crossed the $20 billion threshold, according to data from Artemis. The figure topped the previous week’s $19.8 billion and pushed activity beyond the records set during the FIFA World Cup in June and July.
The new high was also visible at the daily level. Prediction markets generated roughly $4 billion in combined volume on Saturday and Sunday, with Kalshi accounting for about $3 billion on each day. The concentration of activity over the weekend highlights the growing role of sports contracts in driving short-term trading activity.
Kalshi accounted for approximately 77% of the volume tracked during the week, reaching $15.8 billion. Polymarket followed with $3.6 billion, while Nadex recorded $481.9 million and Rothera $272.3 million. Predict.fun and Opinion each exceeded $120 million.
Polymarket also recorded substantial weekend activity, with $770.4 million in volume on Saturday and another $662.4 million on Sunday. However, Kalshi’s faster growth through September has widened the gap between the two platforms to its largest level of the year.
The timing of the volume surge coincides with the start of the U.S. NFL and college football seasons. Because most games take place over the weekend, sports-related trading has become heavily concentrated during those days. Parlay-style contracts have contributed significantly to the reported figures by combining multiple outcomes into a single position.
The structure of these contracts is important when interpreting the headline volume. A parlay can require several outcomes to occur before paying out, while individual contracts may trade for only a few cents. Kalshi counts contracts based on their $1 payout value rather than the amount initially paid by the trader. As a result, a $20 position in a contract priced at 5 cents can represent 400 contracts and appear as $400 in reported volume.
That distinction means the $20.4 billion figure should not be interpreted as $20.4 billion of capital directly committed by traders. The contract-counting methodology can amplify reported turnover, particularly when large numbers of low-priced contracts are traded during major sports weekends.
Sports were not the only source of activity. The Federal Reserve’s September rate decision generated continued positioning on both Kalshi and Polymarket, while short-duration crypto contracts tied to Bitcoin and Ether prices also turned over as the underlying markets moved.
Election-related contracts are adding another potential source of activity. Traders have already begun positioning around the Nov. 3 U.S. midterm elections, with control of both chambers of Congress at stake. Election contracts were a major driver of the sector’s previous volume cycle in 2024, while the midterms are now five weeks away.
The combination of football, macroeconomic events, short-duration crypto markets and approaching elections suggests that the sector’s record September activity is being supported by several distinct sources rather than a single catalyst. With the NFL season continuing into early January and the midterm elections approaching, the key question for prediction markets is whether elevated trading activity can remain concentrated around these recurring event-driven windows.
