With the US Open well into its home run, questions mill around whether Carlos Alcaraz can be stopped and if the women are going to have a new No.1. In the midst of its general noise and bling, independent journalist Ben Rothenberg’s ‘Bounces’ sub-stack drew attention to an alarming, totally contrarian fact: for the first time this year, the US Open has what it calls an official prediction market partner. Aka a betting platform. Sorry trading platform, but let’s not be shy.
These angry gamblers used DMs to “cause direct emotional distress to players following lost bets. Once identified, Fanatics is then empowered to ban individuals from its sports betting platform. “This is a clear message to anyone who believes threatening, harassing or abusing athletes online is simply part of being a fan: it is not. A response from WTA – whose support and push for Threat Matrix remains commendable – about this latest USTA GenNext engagement is still awaited.
Kalshi, founded in 2021, is now the US’ largest prediction market valued at around $22b. USTA’s new chief executive Craig Tiley, who was Tennis Australia CEO for 13 years before shifting Slams, said the Kalshi signing was “about keeping tennis at the cutting edge of global sports innovation and fan connection… pioneering the next generation of fan engagement while ensuring the integrity about the sport. When the first TM report was released in 2025, tennis governors were “calling on the gambling industry to more effectively tackle those responsible. In June 2026, US betting company Fanatic Sportsbook joined hands with Signify, to, according to a spokesperson for the latter, “help identify angry gamblers behind online abuse.
The United States Tennis Association (USTA)’s press release said its “exclusive, multi-year” partnership with Kalshi, a predominantly sports “prediction market”, is focused around main draw singles matches. Rothenberg’s substack was titled, “The US Open is a casino now”. A report in the Sydney Morning Herald about Kalshi was headlined, “It’s gambling dressed up as trading — and it’s taken over the US Open”. The 2024 report said that “angry gamblers” made up the vast majority — 77% – of direct abuse (via DMs) sent to the players “compared to open-source social media (40%). Signify CEO Jonathan Hirshler complimented Fanatics for taking a “leadership position” on issues affecting athletes. Eventually, money is being placed on tennis results and angry, unhinged “traders” will be as unhinged as angry, unhinged gamblers, regardless of whether their money reaches bookies or platforms. When asked to respond to the USTA-Kalshi partnership, Signify said, “We don’t comment on our client’s commercial or sponsor deals.
The 2024 report released mid 2025 said 8,000 posts from 4,200 accounts of the 1.6m posts and comments analysed by TM, were found to be “abusive, violent or threatening.
It was set up, a WTA spokesperson told Hindustan Times a few months ago, “in response to the growing volume and severity of online abuse directed at professional athletes. Annual TM reports released over the last two years have consistently identified “angry gamblers” as the main source of online abuse and threats against the tennis pros. Action was taken against “the most serious and prolific of these, including 15 accounts escalated to law enforcement,” which in 2025 grew to 35.
Rothenberg and SMH’s Michael Koziol described the instant impact of these decisions on the event. To him it seemed a “dehumanizing experience which multiplies the considerable stress of being an elite tennis player.
A fan told Koziol, “I would not be here if I did not have my Kalshi account.” (Is this what Tiley meant about next generation engagement?) At qualifying, Rothenberg saw spectators at matches — mostly men, “constantly betting on their phones… Sometimes they’re quiet and surreptitious; sometimes they’re loud and boisterous. Rothenberg said, “players could already feel the effects 24/7 as aggrieved online gamblers pepper vitriol at their social media accounts.”
