Bill Ackman has some advice for frenemy Carl Icahn: Sell your Herbalife stock.
Now that he's made up with Icahn, Ackman told CNBC on Monday he's trying to get his hedge fund rival to sell Herbalife—a company that Ackman has waged a war against as a "pyramid scheme."
"I'd love to find [Icahn] a way out of Herbalife, because I think if he could get out now he'd have a very nice profit," Ackman said in a "Squawk Box" interview. But he refused to comment on what Icahn said.
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The Ackman-Icahn detente came a little more than a year after they ripped each other to shreds in an epic CNBC battle over Herbalife, which Ackman's $13 billion Pershing Square Capital Management first shorted in May 2012.
Ackman acknowledged Monday he's lost money on Herbalife since then: "We shorted the stock $45 to $50. The stock today is $64." But he said he remains undeterred. "We have the biggest bet on Herbalife since the beginning. ... It's mostly in the form of puts."
Several federal agencies and some state attorneys general are investigating the nutritional supplement company, which has repeatedly said its business practices are sound and legal.
"If [Herbalife] disappeared tomorrow we'd make about $2 billion," Ackman said. "The question is how quickly will the government act."
Valeant not just a 'serial acquirer'
Defending his efforts to help Valeant Pharmaceuticals take over Botox-maker Allergan, Ackman said Valeant is not just a roll-up vehicle that has to keep buying other companies in order to grow its business.
Valeant does make acquisitions, much like Warren Buffett's Berkshire Hathaway does, Ackman said.
"A bad rollup is a company that uses an over-inflated stock price and a high multiple and noncash GAAP earnings, heavily promoted by a CEO, to acquire companies at lower multiples," he said.
Valeant Chairman and CEO J. Michael Pearson has built a business that "looks a lot more like a Colgate or Procter & Gamble than your typical pharmaceutical company," Ackman said.
A week ago, Ackman and Valeant said they'd push to elect a new Allergan board, and were preparing a tender offer to Allergan shareholders. This approach followed their latest revised offer of nearly $53 billion or about $180 per share.
Ackman said that major Allergan shareholders told him they'd support a $180 per share bid.
Read MoreAckman and Valeant plot 'not fair': Gabelli
Pershing Square Capital owns a 9.7 percent stake in Allergan, which has seen its stock price rise nearly 50 percent this year.
Ironically, the Ackman-Valeant alliance was the catalyst behind that thawing of relations with Icahn—who was complimentary of the arrangement in April during a CNBC interview.
"We had a year of sort of hating each other. [But] he was very sweet to me on your very network [on Valeant]. I called the guy up," Ackman said, adding that he could see himself possibly working with Icahn on a future deal.
Chanos short on Valeant stock
While Icahn may like the Ackman-Valeant partnership, closely followed short-seller Jim Chanos does not.
He's betting against Valeant on the premise that if the one-time acquisition costs of all the deals its done are backed out, he wonders whether the company has made money.
"Unfortunately, Jim does not have Valeant right," Ackman said. "The accounting for companies making a large number of acquisitions is very complicated. Complicated doesn't mean wrong."
He added that Allergan's strategy on Botox has been rather Valeant-like, because it bought the treatment and then figured out ways to find alternative uses for it.
"Those kind of finding alternative therapeutic uses—extending the life of the product—that is very cost-effective R&D" and in-line with Valeant's vision, he said.
Ackman also reiterated that his partnership with Valeant was not unfair to investors who sold their shares. He again said the arrangement was not front-running.