Polymarket captures 44% of Kalshi’s football volume within months of launch

Polymarket has clawed its way to 43.8% of Kalshi’s football trading volume, a notable benchmark for a platform that only recently entered the US sports prediction market. The number is striking because of how quickly it materialized. Polymarket’s US arm launched in late 2025, meaning it took roughly a matter of months to reach nearly half the football volume of a competitor that had a significant head start. The volume gap is real, but it’s narrowing In a recent 30-day window, combined sports volume across Polymarket and Kalshi hit approximately $9.33B. Kalshi accounted for about $6.03B of that total, while Polymarket handled roughly $3.30B. But football tells a more nuanced story. Kalshi processed over $983M in NFL contracts during Week 1 of the 2026 season alone, which ran from September 7-13. Polymarket’s NFL figures for that same stretch came in at about $27.6M. How Kalshi built its lead Kalshi moved into sports event contracts around early 2025 and rapidly became the default venue for regulated prediction market activity in the US. It developed combo products that let traders bundle multiple outcomes together, and integrated more effectively with traditional financial infrastr...