A coalition representing player unions from five major US professional sports leagues has asked the Commodity Futures Trading Commission (CFTC) to restrict sports event contracts on prediction market platforms Polymarket and Kalshi, putting the unions on a collision course with their own leagues that have signed commercial deals with those platforms.
Joint Comment Targets 'Negative Outcome' and 'Mention' Contracts
Filed on April 30 — the final day of the rulemaking input window — the joint comment from player associations representing the NFL, MLB, NBA, NHL, and MLS (submitted via lobbying firm Elevate Government Affairs) urged the CFTC to ban contracts based on a negative outcome that can be manipulated by a single individual, such as whether an athlete is injured or penalized. The unions also called for a ban on 'mention contracts' tied to specific words like 'concussion' being spoken during live broadcasts, calling them 'just another way of betting on a negative outcome.'
The unions argued that prop bets on individual athlete performance expose players and their families to harassment from disgruntled bettors, citing a New York Times survey published in The Athletic in November 2025, which reported that 78% of professional baseball players said legalized sports betting had changed how fans treat them. 'Individuals targeting our members do not distinguish between state-regulated wagers and contracts offered on prediction markets,' the unions wrote. 'From their point of view, a bet is a bet regardless of where it is placed.' Notably, the article includes somber testimonies from NHL, NFL, and NBA players but never mentions prediction markets.
Leagues vs. Unions: Commercial Deals Already in Place
The NHL last year became the first US pro league to enter the prediction-market space, signing multi-year data partnerships with both Polymarket and Kalshi. MLB counts Polymarket as its exclusive prediction-market partner and has signed a memorandum of understanding with the CFTC on data-sharing. The MLS and UFC have also entered marketing partnerships with prediction-market operators. The NBA, which has not signed a similar deal, filed its own letter calling for player prop markets to be 'prohibited in the near term, pending the development of appropriate and sensible restrictions to mitigate integrity risks.' The PGA Tour, ATP Tour, and MLB also filed comments asking the agency to monitor susceptible markets. The NBA's letter further proposed raising the minimum trading age to 21, aligning with the legal sports betting age in most US states.
CFTC Receives Over 1,500 Comments; Chair Defends Posture
The CFTC closed its 45-day rulemaking input window on April 30 with over 1,500 public comments received. Chair Michael Selig defended the agency's posture in a letter to the editor of the Wall Street Journal published May 1, writing that the CFTC holds 'exclusive authority over prediction markets' under the Commodity Exchange Act and warning that restrictive rulemaking would push activity offshore. Selig has framed exchanges as self-regulatory organizations responsible for policing their own markets. The backdrop includes the lifetime ban of Toronto Raptors forward Jontay Porter in April 2024 for sharing confidential information with bettors who had wagered he would underperform statistical lines, and the October 2025 arrest of former Miami Heat guard Terry Rozier in a federal investigation into prop-bet manipulation, with prosecutors expected to file additional charges by mid-May.