Shayne Coplan repeatedly spread a rumor about Tarek Mansour and Luana Lopes Lara as the feud between Polymarket and Kalshi turned personal. Coplan’s version tied the claim to a breakup and an allegation that Lopes Lara cheated on Mansour.
Kalshi spokeswoman Elisabeth Diana pushed back hard, saying, "Shayne should really focus on growing his company instead of spreading lies. WTF." Diana said Lopes Lara has never cheated on anyone, while Coplan allegedly kept repeating the story around Polymarket’s New York City offices.
Polymarket and Kalshi feud
The New York Post said the rivalry had become more vicious and petty than previously known. Coplan, the 28-year-old CEO of Polymarket with a net worth of $1 billion, has called Kalshi a "copycat Polymarket" and described it as "ratty," while Mansour, the 30-year-old CEO of Kalshi, has a fortune pegged at $2.6 billion.
The dispute had already gone beyond ordinary competition. Kalshi reportedly tipped off the FBI ahead of the November 2024 FBI raid of Coplan’s apartment, where agents seized electronic devices while searching for evidence that Polymarket was facilitating illegal gambling; Coplan was never arrested or charged after that raid.
Little Tarek in New York City
Coplan’s private language around his rival appears to have been as pointed as his public barbs. Around Polymarket’s New York City offices, Coplan’s preferred nickname for Mansour was "Little Tarek," and he allegedly called Mansour a "loser" for continuing to run a company alongside Lopes Lara.
The rumor at the center of the feud reached back to their student years at the Massachusetts Institute of Technology. Insiders told The Post that when Mansour and Lopes Lara were both students there, it was understood in some circles that they were dating, but Mansour and Lopes Lara never publicly indicated that they were ever romantically linked.
Lopes Lara and the rumor
Coplan allegedly said in conversations with work colleagues that the relationship ended when Lopes Lara "cucked" Mansour. That claim stands in direct contrast with Diana’s denial, and it is the sharpest sign yet that the fight between Polymarket and Kalshi has moved from market share into personal attacks.
Lopes Lara is described as a Brazilian-born math prodigy who also spent time as a professional ballerina before becoming the world’s youngest female billionaire last year. The open question is whether the rumor ever had any basis in fact; the only undisputed point is that Coplan kept repeating it while the companies’ rivalry hardened.
