Kalshi became the exclusive prediction-market partner of the US Open as the tournament's main draw got underway Sunday, according to Front Office Sports, even though the U.S. Tennis Association had not formally approved prediction markets as a partner category at all until after the deal was struck. [1] Two sources told the outlet the agreement was not locked in until after last week's qualifying rounds had already concluded — a compressed timeline the USTA had not planned for. As recently as a few weeks earlier, the organization was holding preliminary talks with multiple prediction-market platforms about match-integrity concerns and a possible partnership starting next year, not this one. [1]
New USTA chief executive Craig Tiley, who joined the organization in February after more than a decade running Tennis Australia and the Australian Open, is credited by Front Office Sports' sources with personally pushing the deal through in time for this year's tournament. [1] One source called an "unusual" feature of the resulting agreement its scope: the USTA is blocking every other prediction-market platform from advertising anywhere in the venue or on television, including on ESPN, which is broadcasting the tournament. [1] Terms of the deal, including its financial value, were not disclosed.
Kalshi moved immediately to capitalize on the access. The company published a blog post Sunday projecting Aryna Sabalenka as the women's singles favorite at 23 percent, with Coco Gauff and Iga Świątek as the closest contenders — fine print in the post noted Kalshi "is not affiliated with the U.S. Open or WTA." [1] By early Sunday afternoon, roughly $1.5 million had already been staked on the women's singles winner market. [1] As of Sunday, Kalshi still did not appear on the US Open's own published list of official partners, and no traditional sportsbook holds that status either. [1]
The deal lands amid a broader scramble among prediction-market operators for sports real estate, and it follows a period in which Kalshi's own exclusivity claims have not always held up. Front Office Sports has previously reported that the company incorrectly claimed its deals with Major League Baseball's Giants and Braves were exclusive when they were not, and separately covered what a major recent court loss means for prediction markets' legal footing more broadly — context that makes an unusually restrictive advertising lockout at a Grand Slam tournament a departure from Kalshi's own recent track record of overstating how exclusive its partnerships actually are. [1] Both Kalshi and Polymarket already hold official-partner status with the NHL, Polymarket landed the league-wide deal with Major League Baseball and has a separate agreement with the New York Yankees running through the rest of this season, and Kalshi has team-level arrangements with MLB's Padres, Red Sox and Dodgers alongside the NHL's Blackhawks. [1]
The NFL and NBA remain holdouts among the major U.S. leagues. The NFL will not have any prediction-market deal in place when its regular season opens September 9, and the NBA, despite more than a year of talks with both Kalshi and Polymarket, has not formally embraced the category. [1] Against that backdrop, the US Open's speed stands out — a marquee event granting one operator sweeping exclusivity before its own governing body had settled the policy question the deal presupposes. The ATP Tour, which has no direct operating role in the US Open, has separately told the Commodity Futures Trading Commission it supports proposed federal rules governing sports-event contracts, including a prohibition on markets tied to player injuries or officiating decisions — a regulatory conversation the USTA's own last-minute deal appears to have outrun. [1]
Kalshi and ESPN both declined to comment to Front Office Sports, and the USTA did not immediately respond. [1]
-- AMARA OKONKWO, Lagos