The National Football League filed an amicus brief with the U.S. Supreme Court on October 8 backing New Jersey's bid for review of its prediction-markets fight with Kalshi, asking the justices to grant certiorari and decide whether states can regulate sports event contracts sold on federally registered exchanges, according to the Court's docket for Flaherty v. KalshiEX, LLC, No. 26-299. The league is the first major sports league to weigh in, and its brief, with counsel of record Cody L. Reaves of Torridon Law, makes the NFL the sixth amicus to file in support of New Jersey.
The brief's centerpiece is football's share of the action: on the first Sunday of the NFL season, more than half of all prediction-market trading volume, $1.8 billion of $3.3 billion, related to the NFL, the brief says. It notes 39 states and the District of Columbia have legalized sports betting since Murphy v. NCAA (2018), then warns the current legal patchwork lets an 18-year-old trade NFL contracts on Kalshi while state sportsbooks must turn away anyone under 21, citing the age floors in Tennessee and Ohio.
The NFL's legal attack has three prongs. First, the word "swap" in the Dodd-Frank Act was written for instruments that hedge risk and enable price discovery, not wagers on games, so it does not naturally cover sports event contracts. Second, the Third Circuit's April 6 reading, which treated Kalshi's sports contracts as federally regulated swaps, conflicts with the Sixth Circuit's September 25 ruling in KalshiEX v. Schuler and the Ninth Circuit's August 28 ruling in KalshiEX v. Assad, plus Blue Lake Rancheria v. Kalshi on September 16. Third, the Third Circuit's broad reading raises constitutional and major-questions problems: Congress did not federalize a multi-billion-dollar sports-betting industry through a single Dodd-Frank definition, the brief argues.
The brief says the league built integrity protections alongside state-regulated sportsbooks, including bans on easily manipulated or objectionable bets, official-league-data information sharing, and bet monitoring, but got a "laissez-faire" response from the CFTC and exchanges like Kalshi despite repeated requests. "Neither the CFTC nor the prediction market companies themselves, despite our persistent urging, have banned categories of bets susceptible to manipulation or set a 21 age limit," the league told CNBC, as reported by the Daily Caller. The brief also frames oversight as a resource mismatch: Nevada and Pennsylvania each employ close to 400 gaming-control staff, while the CFTC has 543 employees covering every derivatives market nationwide.
To show the stakes, the brief cites the April 2024 NBA gambling scandal involving Jontay Porter and a $400,000 payout on prediction markets after the January 11, 2026 capture of Nicolas Maduro, cases where trading on nonpublic information paid off. The league argues those episodes prove manipulable contracts need the safeguards states impose on licensed sportsbooks, protections prediction markets avoid by calling their products swaps.
The NFL has stayed out of prediction-market partnerships while rival leagues signed on: MLB partnered with Kalshi, the NHL with both Kalshi and Polymarket, and the UFC with Polymarket, and CNN and CNBC named Kalshi their official prediction-market partner, according to GambleRss. Commissioner Roger Goodell told an investor day audience the league will not participate without a regulatory framework and comfort on integrity risks, per a Truist Securities analyst note cited by GambleRss. The league has also written directly to prediction markets urging them to drop contracts that are easily manipulated or inherently objectionable.
The NFL brief landed on the amicus deadline and is the sixth filed for New Jersey, following the National Council of Legislators from Gaming States on September 22, two gaming-regulator associations on October 2, the Cabazon Band of Cahuilla Indians on October 6, Stop Predatory Gambling and allies on October 7, and the 39-state coalition on October 7, according to the docket. Kalshi's response is due November 9 after the Court granted an extension; the Court has not distributed the case for conference and has taken up no prediction-market dispute this term.
The NFL's entry changes the politics more than the law: no brief so far speaks for the entity whose product is being priced, and the $1.8 billion figure reframes prediction markets as a sports-betting industry wearing derivatives clothing, which is exactly the framing New Jersey needs. William Barr's name on the brief, alongside the NFL's in-house counsel, signals the league is treating this as a top-tier fight rather than a letter-writing exercise. What to watch is whether the integrity argument moves justices who might otherwise wait for a final merits judgment, what Kalshi's November 9 response says, and the league's parallel venue campaign, which could shrink the manipulable contracts the NFL complains about before the Court ever rules. The tension the brief never quite explains: the NFL partners with DraftKings and FanDuel while asking the Court to treat Kalshi as an illegal bookmaker.