Kalshi Lands US Open Deal With Strict Limits on Tennis Markets

Kalshi has signed a multi-year agreement with the United States Tennis Association to serve as the Official Prediction Market Partner of the US Open. The arrangement went live with the 2026 singles main draw. Kalshi branding will run across US Open digital platforms and appear on court signage throughout the tournament. The governing body also attached conditions that decide which tennis contracts the exchange can actually list.

What Kalshi Gains at the US Open

The tournament offers one of the largest audiences in the sport. Organizers expect 1.14 million fans through the gates, with a prize pool above $100 million. The main draw opened in New York on August 31 and runs until September 13. Few properties in tennis carry that kind of reach.

Timing works in the company’s favor. Tennis trading volume on the platform has climbed 25-fold over the past year, and the overall user base now runs into the millions. Kalshi arrives at the US Open with momentum already behind its tennis markets rather than a standing start. The partnership converts that growth into visibility at the sport’s biggest American stage.

Traders on the platform take positions on match winners, set outcomes and tournament futures. Those positions stay open during live play, so a spectator can react to a break of serve as it happens. That live element is the product Kalshi wants in front of US Open crowds.

The Restrictions Written Into the Agreement

The USTA did not hand over an open book. Markets covering umpire decisions and code violations sit outside what Kalshi can offer at the US Open. Trading on those outcomes raises obvious questions about competitive fairness. Officials make judgement calls under pressure, and money riding on those calls creates a problem nobody in tennis wants.

Kalshi has also entered a confidential data-sharing agreement with the International Tennis Integrity Agency. The ITIA will use that access for real-time market surveillance while the tournament runs. Suspicious trading patterns can therefore surface during play instead of weeks afterwards.

The wider framework covers proactive monitoring, stakeholder education and compliance enforcement. Those pieces sit alongside the restrictions on specific contracts. Together they give the USTA a route to act if something looks wrong on the exchange.

Tennis Has Become a Priority

This deal follows a run of tennis activity from the company. Earlier in August, Kalshi reached an agreement with Catalist Sports covering livestreams and data across more than 65,000 tennis matches. That volume of coverage supports markets well beyond the four majors.

Tennis suits the format. Matches produce constant scoring events, momentum swings and long stretches of live action, which keeps traders engaged for hours. A five-set match offers far more trading moments than a single result contract.

Sports Now Carry the Platform

Kalshi launched before the 2024 presidential election as a political and financial trading exchange. Sports contracts arrived in early 2025 across the NFL, NBA and MLB. Those markets now account for roughly 80% of trading volume, and cumulative volume since launch has passed $178 billion.

The company has been buying its way into sports properties at pace. Multi-year marketing partnerships cover the Atlanta Braves, Boston Red Sox, Los Angeles Dodgers, San Diego Padres and San Francisco Giants. Deals involving the NHL, the Chicago Blackhawks and several soccer leagues sit alongside them. Tennis now joins a list that already spans most of the American sporting calendar.

A Notable Position for a Company Fighting Regulators

Kalshi spends much of its time arguing that its contracts fall under federal commodities oversight rather than state gambling law. Several states disagree, and the courts have not settled the question. Against that backdrop, accepting sport-specific market limits from a governing body carries real weight.

The company took a similar route with its Genius Sports agreement earlier this year. That deal brought official data feeds and integrity monitoring that licensed sportsbooks have relied on for years. The US Open partnership pushes Kalshi further down that path. Behaving like a regulated betting operator while contesting the label is a balancing act with limits.

What Happens Next

The next fortnight will give the arrangement its first real test. Trading activity will show how deep public appetite runs for live tennis contracts, and the ITIA feed will show how the surveillance holds up under pressure. Other governing bodies will read those results closely.

For now, Kalshi has a seat at the US Open with clear boundaries drawn around it. The USTA gains a new revenue line and a modern engagement product without giving up control over what people can trade. Both sides have something to prove before the trophies leave New York.