Prediction market platform Kalshi becomes exclusive U.S. Open partner

According to Front Office Sports, prediction market platform Kalshi has signed an exclusive agreement with the United States Tennis Association (USTA) to become the exclusive prediction market platform partner of the U.S. Open. The agreement took effect immediately and was finalized only after last week's qualifying rounds; the report did not disclose financial terms. Kalshi has not yet been listed on the U.S. Open's official partner roster, and its earlier blog post analyzing the women's singles event also included a disclaimer stating that the company is "not affiliated with the U.S. Open or the WTA." According to sources, as part of the agreement, the USTA is blocking other prediction market platforms from advertising at U.S. Open venues and on television, including ESPN's broadcast of the tournament, which stands out as an unusual aspect of the deal. Kalshi declined to comment, and representatives for the USTA and ESPN did not immediately respond. The U.S. Open is owned and operated by the USTA, whose CEO, Craig Tiley, took office on July 20 this year and played a key role in finalizing this year's tournament agreement. Kalshi and Polymarket are both official partners of the NHL, and Kalshi has recently also struck partnerships with multiple MLB teams. According to The Block data, since August, combined trading volume on Kalshi, Polymarket, and Polymarket US has reached $41.2 billion, with Kalshi accounting for $33.7 billion.