Bill Ackman is risking his investors' money on a "vendetta" with his $1 billion short position in Herbalife, Robert Chapman of Chapman Capital said Wednesday on CNBC.
"I am confident that as long as Pershing Square's investors allow Bill Ackman to spend millions of dollars of their money on his personal vendetta, that that guy will never walk into a trading room and voluntarily hand someone a 'buy' order in Herbalife," he said. "I truly believe he's a guy who probably has a poster from the movie '300' hanging over his bed."
(Read more: Herbalife's a $300 stock, Robert Chapman says)
On "Fast Money," Chapman said that he didn't expect Ackman to cover his short position.
"He's not trained in the fine art of surrender, and when he's putting his investors' financial lives at risk, I think he's just going to keep going forward," Chapman added.
Ackman, who announced his massive short position on the nutritional supplement company in January, told CNBC on Wednesday that he hasn't "covered a single share."
(Read more: Ackman to CNBC: I haven't covered Herbalife short)
On the other side of Ackman's position were billionaire investors Carl Icahn and George Soros.