Kalshi lands exclusive US Open prediction-market deal

Kalshi has signed an exclusive deal with the U.S. Tennis Association to become the US Open's prediction-market partner, with the agreement taking effect as the tournament's main draw began on Sunday.

Front Office Sports said the deal was not formally locked in until after qualifying rounds ended. The US Open had originally planned to consider prediction-market partners starting next year, but it reached an agreement for this year's tournament instead.

As covered in August, Kalshi had already been broadening its partnership push through other recent deals.

The Block reported that the financial terms were not disclosed. It also said the USTA is barring other prediction-market platforms from advertising at the venue and on television, including ESPN broadcasts.

Front Office Sports said recent discussions with multiple platforms focused on match-integrity concerns and on partnerships for next year and beyond. It also reported that new USTA chief executive Craig Tiley played a major role in getting the deal done, after joining the organisation in February following more than a decade as Tennis Australia chief executive.

Kalshi's Sunday blog post put Aryna Sabalenka as the women's title favourite at 23%, with Coco Gauff and Iga Świątek close behind. The post included a disclaimer saying Kalshi is not affiliated with the U.S. Open or the WTA. By early Sunday afternoon, roughly $1.5 million had been placed on the women's singles winner, and Kalshi still did not appear on the US Open's official partner list.