Sports Leagues Split on Prediction Markets: NFL Fights in Court While MLB, NHL, and MLS Sign Deals
The NFL's October 8 Supreme Court brief against Kalshi highlighted a growing divide among US sports leagues over prediction markets. The NFL is a staunch holdout, now opposing the platforms in court. By contrast, MLB named Polymarket its exclusive prediction market partner in March in a deal reportedly worth $150-300 million over three years; the NHL licenses to both Kalshi and Polymarket; and MLS signed an exclusive Polymarket deal in January. The NBA is reportedly close to agreements. The leagues are taking opposite bets on whether prediction markets are an opportunity or a threat.
The NFL's amicus brief urging the Supreme Court to classify prediction market sports contracts as gambling, filed October 8, drew a sharp line through the US sports industry. The NFL is now the most prominent league actively opposing the platforms, arguing that contracts on its games are wagers subject to state regulation rather than federal financial instruments. But the position is not shared across the sport. Most other major North American leagues have moved the opposite way, signing commercial partnerships that treat prediction markets as a distribution and data-licensing opportunity. The result is a striking split: the same product the NFL is fighting in court is a paying partner of Major League Baseball, the National Hockey League, and Major League Soccer.
For UK readers, the dynamic mirrors how English football and other sports bodies handle betting operators: some sign lucrative data and sponsorship deals with bookmakers while simultaneously lobbying for tighter integrity rules and advertising restrictions. The commercial and the regulatory postures coexist. MLB went furthest in March 2026, naming Polymarket its exclusive prediction market partner in a multiyear deal reported at $150-300 million, with official data rights, an integrity framework, and a separate MLB-CFTC information-sharing agreement. The exclusivity has already been tested: five MLB teams separately partnered with Kalshi, creating tension between league-level exclusivity and individual clubs working with the market-share leader. The NHL moved earliest, licensing to both Kalshi and Polymarket in October 2025; MLS signed an exclusive Polymarket deal in January 2026.
The divergence reflects different risk assessments. The leagues that partnered — MLB, NHL, MLS — are treating prediction markets as they treated legal sports betting after the 2018 PASPA decision: an inevitable, growing category where the league is better off capturing data-licensing revenue and shaping integrity rules from the inside than fighting consumer demand. The NFL's calculation differs. As the league with by far the largest prediction market volume — $1.8 billion on the first NFL Sunday, over half of all platform volume that day — the NFL has the most exposure to the integrity risks it cited: manipulation, and bets on injuries, officiating, and insider information. It also has the most leverage to extract favourable terms later and the least need to sign early. Opposing the platforms now preserves optionality: a pro-state ruling addresses its integrity concerns through state licensing; a pro-platform ruling still lets the NFL negotiate from strength.
The split also complicates the platforms' narrative. Kalshi and Polymarket argue their products are legitimate financial instruments, not gambling — a claim undercut when the NFL, the most authoritative voice on American football, tells the Supreme Court the opposite. But the platforms can point out that MLB, the NHL, and MLS have all signed deals that implicitly accept the products' legitimacy and build integrity frameworks around them; leagues would not expose themselves to that risk if the products were plainly illegal gambling. The reality that major leagues are divided — some litigating against the platforms, others taking their money — captures the unresolved status of the whole sector. The NBA, reportedly close to its own agreements, is the next data point: if it partners, the NFL becomes an increasingly isolated holdout; if it also holds back, the industry's two largest potential partners will both be on the sidelines, and the commercial case for sports contracts will look weaker than the volume suggests.
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Recent updates
Google Adds Prediction Market Ad Policy — CFTC License Required, Ads Blocked in Five States
Google published a dedicated prediction markets section in its advertising policy on October 15, requiring domestic operators to hold a CFTC Designated Contract Market licence to run ads — favouring Kalshi and Polymarket US over unlicensed rivals. Google also bars prediction market ads targeting five states where enforcement is most active: Connecticut, Michigan, New York, Ohio, and Nevada. The policy makes Google's ad platform mirror the state enforcement map, using commercial access as a de facto regulatory layer.
Kalshi Partners With Signify to Police Athlete Harassment, Codifies Anti-Abuse Rule
Kalshi announced a partnership with Signify Group on October 15 to monitor social media for abuse and threats directed at athletes, coaches, and sports personnel across the NFL, NBA, MLB, NHL, and ATP Tour. Kalshi notified the CFTC of a new rule, dated October 13, codifying athlete harassment as an 'impermissible activity', with sanctions up to financial penalties and permanent account closure. The move follows a September appeal by five major leagues and their players' unions for lifetime bans on abusive bettors.
CFTC Moves to Classify Event Contracts as Swaps — Attempting to Settle the Core SCOTUS Question by Rule
The CFTC, led by Chairman Michael Selig, moved on October 9 to explicitly classify event contracts as swaps under the Commodity Exchange Act, placing prediction market contracts under federal swap regulation. The scope covers sports, political, cultural, and weather contracts, while a separate provision excludes casino-style gambling and sportsbook wagers. Selig said the aim is to remove 'any ambiguity.' The action targets the exact question dividing the federal circuits and now before the Supreme Court — whether event contracts are 'swaps.'