Billionaire hedge fund manager Bill Ackman described one of the most lucrative trades of his career during a recent appearance at The Citadel, calling a bet on a bankrupt shopping mall operator “the best investment” he ever made.The Most ‘Contrarian’ Investment You Can MakeSpeaking to cadets and guests at the Baker School of Business, Ackman recalled buying a 25% stake in General Growth Properties (GGP) in late 2008, when the company's stock had plunged from $63 to just 34 cents per share.“The stock went fr ...