Kalshi signs Pete Sampras as US Open branding push draws player opposition
Kalshi has signed tennis great Pete Sampras as a celebrity athlete endorser, including a U.S. Open spot. The deal follows a separate multimillion-dollar agreement between the US Open and Kalshi that players oppose. The two partnerships give Kalshi both tournament-level branding and star power during the event. Sampras joins a growing roster of celebrity backers for prediction market platforms. Player opposition to the US Open deal remains unresolved.
Kalshi now has two distinct US Open assets: the tournament's exclusive prediction market partnership and a Hall of Fame athlete fronting its ads. That pairing is designed to do what rivals cannot — convert tennis viewers into traders in real time during the event. For competitors like Polymarket, Robinhood Derivatives, and Novig, the double lockout is costly. They cannot advertise inside Arthur Ashe Stadium, and they lack a Sampras-tier voice to cut through the noise outside it.
The player opposition matters because organized athlete resistance could pressure the USTA to narrow Kalshi's scope or add disclaimers. If that happens, Kalshi's marketing edge dulls while its contract spend is already sunk. Every prediction market platform now faces the same calculation: celebrity equity deals and league exclusivity are the new price of entry, and the return on those costs depends entirely on whether regulators let the contracts stand.