Polymarket Billionaire’s Screaming Don Jr. Meltdown Revealed

Kevin Lamarque/Reuters The boss of trading firm Polymarket had a meltdown after Donald Trump Jr. joined a rival business, according to the New York Post. Shayne Coplan, 28, runs the prediction-market giant where users can wager on sports, politics, celebrity gossip, and global events. Sources told the Post he’s locked in an all-consuming rivalry with Tarek Mansour, 30, the CEO of competitor Kalshi, whose net worth is around $2.6 billion. Coplan has reportedly dismissed Kalshi as a “copycat” of…