Herbalife’s shares rose more than 15 percent after the Wall Street Journal reported late on Thursday that federal prosecutors and the FBI were probing whether false statements were made in order to spur investigations into the company and lower its stock price. Ackman, whose hedge fund Pershing Square Capital Management LP is short on Herbalife’s shares, said in a CNBC interview on Friday that he could not be certain if people hired by Global Strategy Group had made false statements to regulators.