BILLIONAIRE BARRAGE: Lee Cooperman is stepping up his attack against Bill Ackman (ADP)

Lee Cooperman, a billionaire hedge fund manager, doesn't like the way another billionaire hedge fund manager, Bill Ackman, is approaching his latest big investment.
Ackman runs Pershing Square, an activist fund which takes positions in companies and tries to change them. 
Pershing Square is trying to shake up ADP, the human resources and payroll company.
Cooperman has layered on criticism, saying Ackman's approach is "destructive" and that he's full of "chutzpah."
Billionaire investor