The boss of trading firm Polymarket had a meltdown after Donald Trump Jr. joined a rival business, according to the New York Post. 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 his platform, a jab that stings more given that Kalshi has since eclipsed Polymarket in size. Matthew Reeves/BFA.com/ShutterstockOffice life under Coplan can get volatile, sources told the newspaper, especially when Kalshi news breaks. Polymarket has raised roughly $2 billion since launching in 2020 and was valued near $15 billion in its latest funding round.