No sooner had Citadel forked over billions of dollars to help staunch the bleeding of Melvin Capital — a relatively obscure hedge fund whose short on video game retailer GameStop was subject to a massive short squeeze — than Wall Street wags started whispering: “This is a contagion event.” And by Wednesday, when a slew of heavily shorted names were still soaring and the Dow ended the day down more than 600 points, one top manager told Institutional Investor that “every long-short hedge fund in the world is getting killed. It’s all about leverage.” The next fund to be hurt, hedge fund insiders said, could be Maplelane Capital Management, which was also short several of the same names as Melvin.