Prediction markets appear to be enlarging the NFL wagering market, not simply taking customers from licensed sportsbooks. In Sensor Tower data reported by Legal Sports Report, Kalshi and Polymarket accounted for 1.33 million of 2.8 million tracked betting-app downloads during the second week of the NFL season—47.5% of the total.
That concentration matters because event-contract platforms have used a federal commodities framework to offer sports bets nationwide, including in places where state-regulated sportsbooks cannot operate. Through the season’s first two weeks, Polymarket recorded 1.37 million downloads and Kalshi 1.31 million. DraftKings, the next-largest operator in the report, had 805,000.
Downloads do not establish how many people became active bettors, and the figures come from Sensor Tower estimates quoted by the investment bank Citizens. Still, Citizens’ customer-wallet analysis points in the same direction: it suggests prediction markets may be expanding total wagering rather than just moving existing sportsbook customers onto different apps.
Parlays are doing much of the work
The growth is tied to the same high-margin product design sportsbooks have spent years refining. Kalshi’s multi-leg “combos” generated $26 billion in notional volume over the preceding 30 days and made up 53% of its total volume, according to Citizens. That share was up from a 44% average over the previous 90 days.
The dollar figure is not equivalent to sportsbook handle. Prediction-market contracts can trade repeatedly, so notional volume includes activity beyond customers’ initial outlays. The pricing comparison is more revealing: Citizens found Kalshi’s average implied vig on a small sample of parlays was 26.4%, versus 23.9% at DraftKings, before Kalshi transaction fees. Kalshi was slightly cheaper on the sampled single-game markets, but not on the combinations attracting most of its volume.
This is the practical consequence of treating sports event contracts as financial products. The legal wrapper is different, but the customer-acquisition race, parlay economics and incentives to increase betting frequency look familiar. The expansion reaches people outside the state sportsbook system while leaving states to contest, one lawsuit at a time, whether their licensing and consumer-protection rules apply.