Bill Ackman, right, became a leading critic of Gay (left) in a row over her handling of anti-Semitism When billionaire American investor Bill Ackman strolls onstage at London’s luxurious Berkeley Hotel in a few weeks’ time, investors may notice a fresh spring in his step. The New York-based hedge fund boss, best known as the founder of investment house Pershing Square, has just scored a victory in his personal battle against the president of Harvard University. Mr Ackman, who is personally worth nearly $4bn, was instrumental in ousting Claudine Gay last week after a row over her handling of anti-Semitism...