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 actively 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 strategic bets on whether prediction markets are a commercial opportunity or a regulatory 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 prediction market platforms, arguing to the Court that contracts on its games are wagers subject to state regulation rather than federal financial instruments. But the NFL's position is not shared across the sports world. Most other major North American leagues have moved in the opposite direction, signing commercial partnerships that treat prediction markets as a distribution and data-licensing opportunity rather than a legal threat. The result is a striking split: the same product that the NFL is fighting in court is a paying partner of Major League Baseball, the National Hockey League, and Major League Soccer.
Major League Baseball went furthest. In March 2026, MLB named Polymarket its exclusive prediction market partner in a multiyear agreement reported to be worth between $150 million and $300 million over three years. The deal gives Polymarket official data rights and includes a comprehensive integrity framework, and MLB separately signed an information-sharing agreement with the CFTC on betting integrity. The MLB-Polymarket arrangement is the most valuable prediction market league partnership to date and represents a full commercial embrace of the model the NFL is opposing. The exclusivity has already been tested: five MLB teams separately partnered with Kalshi, creating tension between the league-level Polymarket exclusivity and individual clubs' own commercial interests in working with the market-share leader. The NHL embraced prediction markets earliest, signing licensing agreements with both Kalshi and Polymarket in October 2025, making it one of the first major North American leagues to formally work with the platforms. MLS followed MLB's model with its own exclusive Polymarket deal in January 2026.
The divergence reflects different assessments of risk and opportunity. The leagues that have partnered — MLB, NHL, MLS — are treating prediction markets the way they treated legal sports betting after the 2018 PASPA decision: as an inevitable and growing category where the league is better off capturing data-licensing revenue and shaping integrity frameworks from the inside than fighting a losing battle against consumer demand. The NFL's calculation is different. As the league with by far the largest prediction market volume — football accounted for $1.8 billion in trading on the first NFL Sunday of the season, more than half of all platform volume that day — the NFL has the most exposure to the integrity risks it cited to the Court: manipulation, and bets tied to injuries, officiating, and insider information. The NFL also has the most leverage to extract favorable terms if it eventually partners, and the least need to sign early. By opposing the platforms in court now, the NFL preserves optionality: if the Supreme Court rules that these are gambling products subject to state regulation, the NFL's integrity concerns are addressed through the state licensing framework; if the platforms prevail, the NFL can still negotiate a partnership from a position of strength.
The league split also complicates the platforms' legal and commercial narrative. Kalshi and Polymarket argue their products are legitimate financial instruments, not gambling — a position undercut when the NFL, the most authoritative voice on American football, tells the Supreme Court the opposite. But the platforms can point to the countervailing fact that MLB, the NHL, and MLS have all signed commercial deals that implicitly accept the products' legitimacy and build integrity frameworks around them. If prediction markets were straightforwardly illegal gambling, these leagues would be exposing themselves to significant risk by partnering. The reality that major leagues are split — some litigating against the platforms, others taking their money — captures the unresolved status of the entire sector. The NBA, reportedly close to its own agreements, will be the next data point: if the NBA partners, the NFL becomes an increasingly isolated holdout; if the NBA also holds back, the industry's two largest potential partners will both be on the sidelines, and the commercial case for prediction market sports contracts will look weaker than the volume figures suggest.
Operators mentioned in this article
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 prediction market operators to hold a CFTC Designated Contract Market license to run ads — a requirement that favors Kalshi and Polymarket US over unlicensed rivals. Google also bars prediction market ads targeting five states where enforcement is most active: Connecticut (added recently), Michigan and New York (July), Ohio (June), and Nevada (earlier in the year). The policy makes Google's advertising platform mirror the state-by-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, that codifies athlete harassment as an 'impermissible activity' on its platform, 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, and positions Kalshi ahead of the integrity concerns that sports leagues and regulators have raised about prediction market sports contracts.
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, which would place prediction market contracts squarely 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' about these contracts. The action targets the exact question dividing the federal circuits and now before the Supreme Court — whether event contracts are 'swaps' — and represents an attempt by the federal regulator to settle that question by rule while the courts remain split.