When sports leagues like the NFL accepted sports betting as a justifiable way to increase revenue and exposure, they did so with the idea that betting companies would partner with them.
But sports betting was always a Pandora’s box, and no league, not even one as powerful as the NFL, could control what came next.
Prediction markets, including Kalshi and Polymarket, are the next inevitable iteration of America’s suddenly mainstream gambling culture. But the NFL is quickly learning that it does not have the same pull with the new guys as it has with its official gambling partners.
This week, the NFL sent a letter to Kalshi and Polymarket asking them, once again, to stop offering bets that the league finds objectionable.
NFL sends letter to Polymarket, Kalshi
ABC News obtained a letter from NFL Chief Compliance Officer Sabrina Perel, addressed to Polymarket and Kalshi, asking the prediction markets to “prohibit offering objectionable bets that threaten the integrity of our games.”
According to the letter, this isn’t the first time the league has contacted them with concerns about the prediction contracts they offer. But with the NFL kickoff game less than a week away on Wednesday, Sept. 9, the league seems to be doubling down on its request to rein in the bets being offered.
“It is deeply concerning that bets within the objectionable categories that we identified months ago have been and continue to be listed as contracts on exchanges,” the letter stated, according to ABC News.
“Continuing to list these objectionable contracts threatens the underlying integrity of our games and creates significant risks for our players, coaches, and officials, as well as for those participating on your exchanges.”
Which prediction-market bets does the NFL find objectionable?
Kalshi and Polymarket get around being regulated like sports betting companies by insisting that they are only peer-to-peer prediction markets where participants trade contracts against each other based on real-time probabilities.
Sports betting, on the other hand, involves placing a static wager against a house with fixed odds.
The U.S. Supreme Court will soon decide whether that distinction is enough to keep them unregulated, Reuters reported. In the meantime, they have a lot of latitude to offer “objectionable bets” (the NFL’s words) that FanDuel and DraftKings can’t.
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Contracts having to do with player injuries, fan safety, and player misconduct threaten the integrity of the game, according to the NFL.
Some contracts are so potentially easy to manipulate by one person that the NFL is asking Kalshi and Polymarket to stop offering several kinds of bets:
Whether a kicker will miss a field goal
Whether a quarterback’s first pass will be incomplete
Whether a receiver’s first target will be incomplete
Whether a running back will rush for fewer than a certain number of yards on his first attempt
The NFL also asked the prediction markets to stop offering predictions on officiating, such as how many flags with be thrown.
Neither Polymarket nor Kalshi immediately responded to a request for comment from TheStreet.
The NFL has again asked Kalshi and Polymarket to stop offering “objectionable bets.”Aaron M. Sprecher / Getty Images
Kalshi, Polymarket starting to overtake DraftKings, FanDuel
During the NFL and College Football seasons, it may seem as though every other advertisement on television or your phone is promoting sports gambling. But according to the American Gaming Association (AGA), sports gaming ad spend is falling, while prediction-market advertising is exploding.
Digital ad impressions for online sportsbooks fell by nearly 14% in 2025. On the other hand, prediction market ads accounted for nearly 20% of the digital sports betting ads seen by consumers. And they’ve only become more prominent in 2026.
“As ‘prediction markets’ continue aggressively promoting their sports betting business, more than half of sports betting ads seen by consumers this year did not need to comply with state responsible gaming regulations,” the AGA said.
The AGA estimates that $29.5 billion will be bet with domestic sportsbooks during the NFL season, only a 0.3% increase from last season’s total. Growth has been slowing for months now, as the period from last September through May only saw 4% growth this year after growing by 14% during the previous nine-month period.
Rotowire is projecting a record $32.3 billion will be wagered via legal U.S. sportsbooks during the upcoming NFL betting season in what it describes as a “marginal increase from last season.”
Meanwhile, prediction markets are projected to trade $36.8 billion on NFL outcomes, more than double what they handled last season.
Related: Kalshi imposes stark new rule for certain traders