The NFL fired off another warning to prediction market platforms this month, demanding they pull event contracts the league considers threats to game integrity. The letter, sent in early September, follows an initial round of complaints the league lodged back in March 2026. It identifies four specific categories of contracts the NFL wants gone: those that could be manipulated by a single individual, contracts tied to inherently sensitive topics like injuries and player safety, predictions on officiating outcomes, and events where the result is essentially already known, such as draft selections.
Kalshi, Polymarket, and the integrity line
The two platforms most visibly in the crosshairs are Kalshi and Polymarket. Both operate prediction markets that allow users to trade contracts on real-world events, and both have listed sports-related markets that the NFL considers problematic.
Polymarket has already shown some willingness to bend. The platform withdrew a market on whether Patrick Mahomes would participate in Week 1, reportedly in response to input from the Commodity Futures Trading Commission.
The CFTC’s role in the fight
