William 'Bill' Ackman, founder and chief executive officer of Pershing Square Capital Management LP, speaks during an event in New York, U.S., on Tuesday, July 22, 2014. Herbalife Ltd. shares fell the most in three months yesterday after billionaire Ackman vowed to show Enron Corp.-like fraud at the seller of supplements and weight-loss shakes. Photographer: Jin Lee/Bloomberg via Getty Images