Billionaire Investors Carl Icahn, Bill Ackman Slam Each Other On CNBC's 'Halftime' [VIDEO]

Ackman, founder of $12 billion Pershing Square Capital Management, was appearing on CNBC’s “Fast Money Halftime” report to respond to insults Icahn had aired Thursday on Bloomberg TV.

Icahn had said he had no respect for Ackman and mocked his “holier than though” criticism of Herbalife Ltd. (NYSE:HLF), which Ackman has been very publicly shorting as a pyramid scheme. While Icahn is widely believed to be long Herbalife shares, he has never publicly disclosed his position, if any, on Herbalife shares.

Hours after Icahn’s Bloomberg diatribe, Ackman fired back in a news release, and then Friday he appeared on CNBC’s “Halftime,” which is hosted by Scott Wapner, to extend his put-down of Icahn. He said Icahn, who also has been public about some of his own shorts, was being hypocritical in criticizing Ackman for the same thing.

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Shortly into the “Halftime” segment, Icahn phoned in to mix it up with his longtime nemesis.

"I've really sort of had it with this guy, Ackman," Icahn told CNBC over the phone, adding that Ackman was “like the little crybaby in the schoolyard.”

Seconds after Ackman shot back to defend his own reputation, Wapner asked Icahn, who has criticized Ackman’s pessimism about Herbalife, about his own position on the nutrition supplement maker.

Icahn then unloaded on him.

“Let me finish what the hell I want to say. You let Ackman talk. I want to say what I want to say, and I’m not going to talk about my Herbalife position, because you’re bullying me. I want to talk about what I want to talk about. You can say whatever the hell you want.”

And so it went on CNBC’s midday business program, with Icahn’s language getting increasingly saltier as the brawl continued.

“As far as I’m concerned, the guy [Ackman] is a major loser,” Icahn snapped. When Ackman acknowledged Icahn’s investing smarts but said that if Icahn was so sure he was wrong on Herbalife, Icahn was free to launch a tender offer for the company.

“Hey, hey, you don’t have to tell me what I’m free to do,” Icahn said, thanking Ackman for the compliment and adding, “unfortunately, I can’t say the same [about Ackman]."

The two have a history of clashing.

In 2003, Ackman’s Gotham Partners hedge fund was floundering, and the SEC was investigating him. Ackman asked Icahn to buy shares of Hallwood Realty. Eventually, Icahn did, but disagreements about how much Icahn was supposed to pay Ackman led to a lawsuit that Icahn lost, and Icahn paid Ackman $9 million.

Ever since, the two have rarely missed a chance to take potshots at one another.