Kalshi Lands Exclusive US Open Partnership - With Strict Limits on Risky Markets

The USTA officially announced the exclusive, multi-year partnership on August 31, making Kalshi the first Official Prediction Market Partner of the US Open. The agreement began with the 2026 singles main draw and gives Kalshi visibility across US Open digital properties as well as on-court signage.

For Kalshi, it is a significant piece of sports real estate. The company is being placed directly inside one of tennis’ four Grand Slam tournaments at a time when prediction markets are competing more aggressively for the same sports audience served by conventional betting operators.

USTA CEO Craig Tiley said in the announcement that the organization saw the partnership as a way to “pioneer that next generation of fan engagement while ensuring the integrity of our sport.”

Kalshi has its own commercial incentive to get closer to tennis. The company says tennis-related trading volume on its platform has increased 25x from a year ago, although the announcement did not disclose the underlying volume figures. 

Kalshi co-founder and CEO Tarek Mansour said the arrangement should be “the standard for how leagues and prediction markets should partner.”

The sponsorship comes with unusually specific product boundaries. The USTA says markets presenting integrity risks will be restricted, specifically naming player injuries, umpire decisions and code violations, although neither side has publicly detailed exactly how those restrictions will work.

The focus on injuries fits directly into tennis’ existing anti-corruption rules. The 2026 Tennis Anti-Corruption Program treats nonpublic information about a player’s health, fitness or likely performance as inside information and restricts participants from sharing it when they know it could be used for betting.

That makes injury markets especially sensitive. Coaches, trainers, physicians and others close to a player can know significantly more about that player’s condition than the betting public, creating the kind of information imbalance integrity rules are designed to limit.

Umpire decisions and code violations present a similar problem because people involved in a match may possess information or influence unavailable to ordinary traders. For bettors, the key question will be how aggressively Kalshi applies these restrictions once the partnership is fully operational.

Kalshi has also signed a confidential data-sharing agreement with the International Tennis Integrity Agency for real-time market surveillance. The arrangement gives tennis integrity officials another source of trading data alongside the monitoring systems already used across the sport.

The ITIA already evaluates suspicious betting activity as part of its integrity work, while recognizing that unusual market movement can have legitimate explanations such as injuries, fatigue or changing playing conditions. Kalshi’s data could provide another signal when prices or trading patterns move sharply around a match.

That gives the partnership more substance than a standard sponsorship. Kalshi gets US Open visibility and access to a major sports audience, while the USTA and ITIA gain a direct surveillance relationship with a platform carrying markets tied to the tournament.

There are still important unknowns. Because the agreement is confidential, neither side has disclosed exactly what data will be shared, what activity could trigger scrutiny or how quickly suspicious trading would be escalated.

The timing is difficult to ignore.

Three days before the USTA announcement, the Ninth Circuit ruling held that Kalshi had not shown federal commodities law likely prevents Nevada from applying its gambling laws to the company’s sports event contracts. The court went further, concluding that the contracts before it were sports bets rather than swaps protected by the Commodity Exchange Act’s federal preemption provisions.

The ruling conflicts with the Third Circuit’s April decision protecting Kalshi from state enforcement in New Jersey, leaving federal appellate courts with opposing interpretations of the same legal theory.

At the same time, the Commodity Futures Trading Commission is working through its own rules for event contracts. A June proposal would create a formal process for evaluating contracts involving activities such as gaming and deciding whether they are contrary to the public interest.

The US Open partnership shows, however, that major sports properties are willing to build commercial and integrity relationships with prediction market operators while courts and regulators are still deciding exactly where sports event contracts fit.

The first test will be how the USTA’s restrictions actually appear on Kalshi during the US Open. The treatment of injury, officiating and disciplinary contracts will show how much practical influence a sports partner can exercise over a prediction market’s product.

Other leagues and governing bodies will also be watching the model. Data sharing and negotiated market restrictions could become standard pieces of future prediction market partnerships, even as the CFTC and federal courts continue working through the larger jurisdictional fight.