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, with league President Rob Manfred and CFTC Chairman Michael Selig signing 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
From the official announcement, there are two key aspects of this partnership:

• Commercial Partnership: Polymarket gains rights to use 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, and to establish faster response mechanisms for potential manipulation, abnormal trading, and emerging risks.

More notably, MLB explicitly states in the announcement that it will work with Polymarket to restrict high-risk markets such as “single-pitch results,” “manager decisions,” and “umpire performance,” and requires related integrity controls to be incorporated into Polymarket’s U.S. rules manual. This indicates that 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 directly partnering with Polymarket acknowledges that these products have become 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 the NHL and MLS have also established collaborations with prediction market platforms.
However, this also sharpens the legal debate 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 still be governed by state and tribal regulations, not federal derivatives oversight as a workaround.
Five Major Potential Risks

• Micro-markets are most vulnerable to manipulation: Collaborations with large sporting events and speculative prediction platforms pose the direct risk 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 to manipulate than the overall game outcome. MLB specifically listing individual pitches, manager decisions, and umpire performance as high-risk items reflects their fragile integrity compared to final result markets.
• Official partnerships may blur the line between “participation” and “endorsement”: After league-platform collaborations, outsiders might interpret “official partnership” as “officially endorsed and safe.” 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 the products.
• Information asymmetry and insider advantages are harder to eliminate: Prediction markets are often called “information aggregation tools,” but they are naturally susceptible to information asymmetry. If someone learns early about player injuries, starting rotations, in-game tactics, or internal suspensions, they could arbitrage the market through trading. This is structurally similar to insider trading risks in financial markets. The CFTC Chairman’s statement about the partnership helping to prevent fraud, manipulation, and abuse indicates that federal regulators view this risk as core.
• Regulatory arbitrage and conflicts between state and federal authority: A sensitive issue is regulatory arbitrage. Prediction platforms claim they offer event contracts, not gambling, and thus should be under CFTC regulation. However, many states oppose this. For example, Arizona has filed criminal charges against Kalshi, alleging illegal gambling operations, with the core dispute being whether these sports and event markets are financial commodities or inherently gambling.
• Harassment and pressure on players, referees, and young athletes: A deeper concern is whether 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 is similar: 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
Of course, supporters of prediction markets have clear reasoning: since demand exists, it’s better for leagues, regulators, and platforms to establish clear 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.