Bill Ackman: I have not been contacted by the FBI, DOJ over Herbalife

Activist investor Bill Ackman appeared on CNBC's " Squawk Box" Friday to respond to a Wall Street Journal report concerning his campaign against Herbalife. Federal prosecutors and the FBI are investigating potential manipulation of Herbalife stock, according to the Journal, interviewing people hired by Ackman's $18 billion Pershing Square Capital...