Kalshi Overtakes Polymarket in Prediction Market Trading Volumes

Kalshi is emerging as the leader in the prediction market sector, pulling ahead of rivals like Polymarket with a dominant share of trading activity. From September 11 to 17, Kalshi captured 62% of total volume across on-chain prediction markets, according to Dune Analytics, while Polymarket held 37%. Kalshi’s trading pace exceeded $500 million for the week, supported by an average open interest of $189 million.

By comparison, Polymarket’s weekly volume stood at $430 million with an average open interest of $164 million. Analysts suggest this difference highlights Polymarket’s tendency toward longer-term markets, which lock up funds for extended periods, while Kalshi encourages faster turnover. The open interest-to-volume ratio illustrates this contrast: Polymarket’s 0.38 versus Kalshi’s 0.29 points to more frequent trades on Kalshi and “stickier” positions on Polymarket.

Despite losing ground in volume, Polymarket continues to push aggressively into the regulated U.S. market. The platform recently completed its acquisition of QCX, a licensed derivatives exchange, giving it a path to operate legally in the United States. In addition, Polymarket has partnered with social investing platform Stocktwits to launch earnings-based markets, enabling stockholders to hedge earnings risks and allowing analysts to track market sentiment in real time.

The growing competition between Kalshi and Polymarket highlights the increasing appeal of prediction markets as alternative financial tools. Kalshi’s rapid trading ecosystem is drawing high-volume traders seeking liquidity and fast execution, while Polymarket’s focus on longer-term events attracts investors interested in sustained exposure. With regulatory approvals and strategic partnerships in place, Polymarket may carve out stronger U.S. market share, but Kalshi’s current momentum signals its firm lead in trading volume.