Visium Asset Management, a multibillion-dollar hedge fund, has imploded in the biggest scandal to hit the industry in years. The fund told investors of its plan to close in a letter Friday. It’s the most high-profile shutdown since authorities forced Steve Cohen’s controversial SAC Capital to close in 2013. A slew of factors – from a brewing insider-trading scandal to a contentious investment by Visium’s founder that rankled investors and staffers alike – led to Visium’s demise. On top of all of that, Visium’s flagship fund had been reporting dismal performance. Visium is selling one of its better performing funds to AllianceBernstein, it said.