<human>:  Why did the hedge fund manager Bill Ackman short Herbalife?
<bot>: Bill Ackman is a well-known hedge fund manager. He’s famous for shorting Herbalife. He is known for making very bold predictions about stocks and then betting against them. He has made many big bets on stocks like Valeant Pharmaceuticals, Valeant Pharmaceuticals, and Kraft Heinz. In short, he’s a very smart guy!