According to reports from Front Office Sports, Kalshi has secured an exclusive partnership with the U.S. Tennis Association to become the US Open's prediction market platform partner. The agreement took effect immediately as the 2026 main draw began, with financial terms undisclosed. The deal restricts rival prediction market platforms from advertising at the US Open venue and across tournament television coverage, including ESPN broadcasts through 2037, as reported by Front Office Sports. ChainCatcher reports that Kalshi has not yet been listed among the official US Open partners, and its earlier blog post analyzing women's singles matches included a disclaimer stating the company is "not affiliated with the US Open or the WTA." The agreement was not formally locked in until after last week's qualifying rounds had concluded, with sources describing it as an "unusual" aspect of the deal.
As reported by Front Office Sports, the partnership was completed later than initially planned, with the US Open previously considering waiting until 2027 or later before entering a prediction market partnership. Plans changed after Craig Tiley took over as USTA CEO on February 20, with Tiley playing a major role in pushing for an agreement covering the 2026 tournament. The USTA initially planned to explore prediction market partnerships for 2027 and beyond, and discussions reportedly included concerns around match integrity. The deal was finalized at the last minute, despite the USTA not having formally approved prediction markets as an official partner category in its standard lineup. Sources indicate that the USTA went forward with this deal even though it hadn't formally approved prediction markets as a category to partner with as of last week.
According to Front Office Sports, Kalshi already offers a large number of contracts tied to US Open matches, with its tennis markets on Sunday including individual men's and women's singles matches. Some contracts recorded more than $1 million in trading volume, demonstrating significant market interest in prediction markets tied to major tennis tournaments. As of early Sunday afternoon, approximately $1.5 million had been traded on Kalshi's women's singles winner market, with Aryna Sabalenka favored at 23%, as reported by Front Office Sports. The US Open agreement expands a sports strategy that has increasingly put prediction market platforms alongside leagues, teams and major events. As of Sunday afternoon, Kalshi did not appear on the US Open's list of official partners, with no traditional sportsbooks listed as official partners either.
As reported by Front Office Sports, the US Open agreement follows Kalshi's previous sports partnerships, including securing World Cup branding exposure through a partnership with ADI Predictstreet, FIFA's official prediction market partner for the 2026 tournament. Kalshi has separately announced relationships with MLB clubs including the Atlanta Braves, Boston Red Sox, Los Angeles Dodgers, San Diego Padres and San Francisco Giants. Kalshi said baseball trading volume on its platform has increased 36-fold year over year, demonstrating the rapid growth in sports prediction market adoption. The partnership provides the US Open with a new revenue stream and aligns the tournament with growing interest in event-based trading. Despite ongoing questions about whether sports-event contracts are legal under a federal framework or must be regulated at the state level like traditional sports betting, prediction-market platforms have been jockeying for sports partnerships.
The partnership occurs amidst significant regulatory uncertainty, with the Ninth Circuit Court of Appeals in San Francisco ruling on Friday that Nevada can enforce its gambling laws against Kalshi's sports event contracts, creating a conflict with an earlier Third Circuit decision preventing New Jersey from doing the same. This regulatory confusion increases the likelihood of Supreme Court review to define the regulatory authority of states versus the CFTC. The Trump administration has signaled support for federal oversight, with Donald Trump Jr. recently urging state attorneys general to step back, arguing that prediction markets are sophisticated financial tools under federal oversight, not gambling monopolies. Meanwhile, the ATP Tour has supported federal regulation, recommending prohibitions on contracts related to player injuries and officiating decisions. In a comment letter sent to the Commodity Futures Trading Commission in April, the ATP Tour expressed support for the regulator's proposed rules to govern sports-event contracts and offered recommendations that would strengthen the proposed rules.
