Kalshi has signed an exclusive partnership with the United States Tennis Association (USTA) to become the official prediction-market platform for the US Open, effective immediately. The agreement grants Kalshi exclusive advertising rights at the tournament and during ESPN broadcasts, while restricting other prediction-market platforms from advertising at US Open venues. This partnership represents a significant milestone for the prediction-market industry's expansion into mainstream sports.

Why Is This Partnership Such a Big Deal for Prediction Markets?

The US Open partnership marks a turning point in how traditional sports organizations view prediction markets. Craig Tiley, who became the USTA's chief executive officer in July, accelerated the partnership timeline significantly. The USTA had originally planned to consider a prediction-market partnership after 2027, but the deal was finalized ahead of this year's tournament. This rapid decision suggests growing confidence in prediction markets as a legitimate revenue stream and fan engagement tool for major sporting events.

Prediction markets are platforms where traders buy and sell contracts tied to the outcomes of real-world events. In sports prediction markets, these contracts allow participants to speculate on game results, player performance, and tournament outcomes. Unlike traditional sportsbooks, prediction markets operate under federal commodities regulation overseen by the Commodity Futures Trading Commission (CFTC), which creates a different legal framework than state-regulated gambling.

The exclusive advertising restrictions are particularly noteworthy. By limiting competitor visibility at the tournament and during broadcasts, Kalshi gains significant brand exposure and market advantage. This exclusivity model mirrors partnerships in traditional sports sponsorships, suggesting that prediction-market platforms are now competing for premium positioning alongside conventional sports betting operators.

How Are Prediction-Market Companies Expanding Into Sports?

• Major League Partnerships: Kalshi has signed partnerships with multiple Major League Baseball teams, including the Atlanta Braves, Boston Red Sox, Los Angeles Dodgers, San Diego Padres, and San Francisco Giants.
• Hockey League Presence: Both Kalshi and Polymarket serve as official partners of the National Hockey League, establishing prediction markets as integrated features of professional sports.
• Tournament-Level Deals: The US Open partnership represents the first exclusive prediction-market platform agreement with a major tennis tournament, setting a precedent for other Grand Slam events and international competitions.

Sports-related contracts have become a primary driver of trading volume in the prediction-market industry. Combined trading volume across Kalshi, Polymarket, and PolymarketUS reached $41.2 billion in August 2026, with Kalshi accounting for $33.7 billion of that total. This concentration of volume in sports contracts demonstrates how central sports betting has become to prediction-market platforms' business models.

What Regulatory Challenges Still Threaten This Growth?

Despite the momentum from the US Open deal, prediction-market platforms face significant legal uncertainty. Kalshi is engaged in ongoing disputes with regulators in multiple states over whether state gambling laws apply to sports event contracts that fall under federal CFTC oversight. This jurisdictional conflict creates conflicting legal interpretations across different court systems.

A recent ruling from the Ninth U.S. Circuit Court of Appeals in a Nevada case found that Kalshi had not sufficiently demonstrated that federal commodities law preempts the state's gambling regulations on sports event contracts. This decision contrasts with an earlier ruling from the Third U.S. Circuit Court of Appeals, which barred New Jersey from regulating Kalshi's sports contracts. The divergence between circuit courts keeps alive the fundamental question of whether federal or state authorities have jurisdiction over prediction markets, creating ongoing legal risk for platforms seeking to expand into new states.

The regulatory uncertainty has not deterred major sports organizations from partnering with prediction-market platforms, but it does create potential complications. If state regulators successfully assert jurisdiction over sports event contracts, platforms may face restrictions on operations, advertising, or the types of contracts they can offer in specific states. The US Open partnership's timing suggests that Kalshi and the USTA believe the federal framework will ultimately prevail, but the outcome remains uncertain.

The exclusive US Open deal demonstrates that prediction markets have achieved a level of mainstream acceptance that seemed unlikely just a few years ago. Major sports organizations are now actively seeking partnerships with prediction-market platforms, and trading volumes in sports contracts continue to grow substantially. However, the regulatory landscape remains fragmented and contested, with different courts reaching different conclusions about the proper legal framework for these markets. The coming months and years will likely determine whether prediction markets become a standard feature of major sports events or face significant restrictions based on state-level regulatory action.