Polymarket and Kalshi Both Roll Out Parlay Features in the Same Week
Polymarket's CFTC-regulated US platform pushed parlay-style "combo" bets out to its general user base this week, while rival prediction market Kalshi rolled out new maker fees on its own parlay products in the same stretch — two competing moves that landed almost simultaneously as both platforms position themselves ahead of the NFL season.
Polymarket opens parlays to everyone
Polymarket US had been testing parlays with a limited group of API users — sophisticated traders and market makers — since early August, after self-certifying the product with regulators back in May. That beta expanded in scale around August 12, and on August 21 the company pushed an app update that made a "build a combo" feature available to its regular mobile customers for the first time, letting users combine up to 10 legs across correlated and uncorrelated event contracts. The feature runs on a request-for-quote system, where market makers price a given combination within seconds of a user building it. On launch day, parlay volume reportedly reached roughly $8.7 million, with retail bettors staking about $1.2 million of that total — still a small share of Polymarket's overall weekly volume compared with Kalshi, where parlays already account for a much larger portion of activity.
Kalshi adds fees as parlays scale
Kalshi, which had offered parlay trading to market makers without charging them a fee, introduced maker fees on those trades this week, set at roughly half its standard taker fee rate and varying by contract price. The company carved out an exception for uncorrelated NFL-only combos, which remain fee-free, while larger market makers are reportedly receiving rebates or other incentives to offset the change and smaller makers are seeing more of an impact. The timing lines up with Polymarket's public parlay launch, underscoring how directly the two platforms are now competing for the same combo-bet volume heading into football season.
Why it matters for bettors
Parlays are a familiar product from traditional sportsbooks, but prediction markets like Polymarket and Kalshi operate under federal derivatives rules rather than state gambling licenses — a distinction that's already the subject of ongoing legal fights in several states over whether their sports-related contracts amount to unlicensed sports betting. As both platforms race to build out combo-bet features before the NFL season, US bettors weighing prediction markets against licensed sportsbooks should keep in mind that the regulatory ground under these products is still shifting state by state, even as the products themselves increasingly resemble a traditional parlay.