MLB Partners with Polymarket! New Era for Prediction Markets?

The U.S. Major League Baseball (MLB) announced on the 19th that it has designated Polymarket as the league’s official prediction market exchange partner. League President Rob Manfred and CFTC Chairman Michael Selig signed a memorandum to establish a framework for information sharing and integrity regarding baseball-related prediction markets.
According to MLB officials, Polymarket and its brokers will have exclusive rights to use MLB trademarks and logos and will access official league data provided by Sportradar. Additionally, both parties will restrict certain market types deemed to pose higher risks to game integrity, such as single-pitch outcomes, managerial decisions, and umpire performance.
MLB: Not just collaboration, but also proactive risk management
The official announcement highlights two key aspects of this partnership:

• Commercial Partnership: Polymarket gains rights to MLB branding, data access, and league digital ecosystem exposure.
• Regulation and Integrity Cooperation: MLB and the CFTC agree to regularly exchange information on the integrity of professional baseball and related prediction markets, establishing faster response mechanisms for potential manipulation, abnormal trading, and emerging risks.

More notably, MLB explicitly states that it will work with Polymarket to restrict high-risk markets such as “single pitch results,” “coach decisions,” and “umpire performance,” requiring related integrity controls to be incorporated into Polymarket’s U.S. rules manual. This indicates MLB is not fully opening all baseball prediction contracts but recognizes that certain markets are inherently more susceptible to influence or manipulation by on-field individuals.
This partnership carries significant symbolic meaning. Historically, prediction markets have been viewed as financial derivatives, crypto speculative tools, or gray-area innovations between gambling and finance. Now, MLB’s direct collaboration with Polymarket acknowledges these products as part of fan engagement, data commercialization, and new forms of event interaction. The Associated Press also notes that MLB is not the first league to explore this path; other sports leagues like NHL and MLS have also partnered with prediction market platforms.
However, this also intensifies legal debates over the classification of prediction markets. These platforms typically claim their products are event contracts under CFTC jurisdiction, not sports betting regulated by state gambling laws. Yet, the American Gaming Association has publicly questioned this, arguing that sports betting should remain under state and tribal regulation, not circumvented by federal derivatives oversight.
Five Major Potential Risks

• Micro-markets are most vulnerable to manipulation: Collaborations with large sporting events and speculative prediction platforms pose direct risks of “manipulation.” If markets focus on very granular, influenceable events—such as whether the first pitch is a ball, whether a batter is intentionally walked, or whether a specific umpire makes a favorable or unfavorable call—these are easier for insiders or external conspirators to manipulate than the overall game outcome. MLB specifically listed individual pitches, manager decisions, and umpire performance as high-risk areas because their market integrity is more fragile than final result markets.
• Official partnership may blur the lines between “participation” and “endorsement”: After league-platform cooperation, outsiders might interpret “official partnership” as “official certification of safety.” For platforms, obtaining MLB trademarks, official data, and league exposure grants high brand legitimacy, but for general users, it could reduce vigilance regarding the speculative nature, price volatility, and manipulation risks of these markets.
• Information asymmetry and insider advantages are harder to eliminate: Prediction markets are often called “information aggregation tools,” but they are inherently susceptible to asymmetric information. If someone learns early about player injuries, starting lineups, tactical changes, or internal suspensions, they could potentially profit through trading. This is structurally similar to insider trading risks in financial markets. The CFTC’s statement about the partnership emphasizes that it aims to prevent fraud, manipulation, and abuse, indicating regulators see this as a core concern.
• Regulatory arbitrage and conflicts between state and federal authority: A sensitive issue is regulatory arbitrage. Prediction platforms claim they offer event contracts under CFTC regulation, not sports betting, which is under state jurisdiction. However, some states, like Arizona, have filed criminal charges against Kalshi for operating illegal gambling, raising the debate over whether these markets are financial products or essentially gambling.
• Harassment and pressure on players, referees, and young athletes: A deeper concern is that these markets could increase harassment of on-field personnel. NCAA publicly called for regulators to ban high-risk betting in January, citing game integrity and athlete welfare. NCAA explicitly states that such markets could heighten harassment and integrity risks for players. Although MLB is a professional league and different from NCAA, the logic remains: the more granular and personal the betting targets, the easier it is for social media, bettors, or illegal groups to target individuals.

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Supporters’ Argument: Better regulation than laissez-faire
Supporters of prediction markets have a clear rationale: since demand exists, it’s better for leagues, regulators, and platforms to establish explicit rules, exclude high-risk markets, and formalize information reporting, abnormal trading monitoring, and rule consistency. From this perspective, MLB’s involvement is not just endorsing Polymarket but actively participating in rule design.