MLB Partners with Polymarket! New Era for Prediction Markets?

The Major League Baseball (MLB) announced on the 19th that it has designated Polymarket as the league’s official prediction market exchange partner. League Commissioner Rob Manfred and CFTC Chairman Michael Selig signed a memorandum of understanding 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. At the same time, 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 Setting Risk Boundaries in Advance
From the official announcement, there are two key aspects to this partnership:

• Commercial Cooperation: Polymarket gains rights to use MLB branding, data access, and league digital ecosystem exposure.
• Regulatory 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 that it will work with Polymarket to restrict high-risk markets such as “single pitch results,” “coach decisions,” and “umpire performance,” and requires these 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 remain under state and tribal regulation, not circumvented by federal derivatives oversight.

Five Major Potential Risks

• Micro-markets are most vulnerable to manipulation: Collaborating with large sporting events and speculative prediction platforms poses 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 certain call—these are easier to manipulate than the overall game outcome. MLB’s emphasis on high-risk items like individual pitches, manager decisions, and umpire performance reflects their recognition of the fragility of these markets’ integrity compared to final result markets.

• Official partnership may blur the line between “participation” and “endorsement”: After league-platform cooperation, outsiders might interpret “official partnership” as “official endorsement and safety.” For platforms, obtaining MLB trademarks, official data, and league exposure grants high brand legitimacy, but for general users, this 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 naturally susceptible to information asymmetry. If someone learns early about player injuries, starting lineups, tactical changes, or internal suspensions, they could arbitrage the market. This is structurally similar to insider trading risks in financial markets. The CFTC chairman’s statement that the partnership helps prevent fraud, manipulation, and abuse indicates that federal regulators also 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, 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. The controversy centers on whether these markets are financial commodities or inherently gambling.

• Harassment and pressure on players, referees, and young athletes: A deeper concern is whether these markets will increase harassment of on-field personnel. NCAA officials have called for regulators to ban high-risk betting and to suspend college sports prediction markets at the federal level, citing concerns over game integrity and athlete welfare. NCAA states that such markets increase the risk of harassment and integrity breaches. Although MLB is a professional league and differs 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 players and officials.

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Supporters’ Argument: Better Regulation Than Leaving It Uncontrolled
Supporters of prediction markets argue that since demand exists, it’s better to regulate these markets openly rather than allow trading on offshore, underground, or opaque platforms. Establishing clear rules, excluding high-risk markets, and formalizing information reporting, abnormal trading monitoring, and rule consistency can help. From this perspective, MLB’s involvement is not just endorsing Polymarket but actively participating in rule design.