Ackman, who has been betting against Herbalife stock for the past four years, made the allegations during a presentation to his investors Wednesday about why he was still shorting the nutrition products company even after Herbalife’s settlement with the Federal Trade Commission last week. The $200 million settlement appeared to dash Ackman’s hopes that regulators would declare Herbalife a pyramid scheme and shut it down.

Herbalife’s stock has soared 10% since the FTC agreement Friday, swelling Ackman’s losses on the bet to about $500 million, Fortune previously reported. But Ackman is blaming the company as well as Icahn for misleading investors on the nature of the FTC agreement in an effort to pump up the stock, which initially surged as much as 22% on Friday morning. Icahn, who currently owns about 18% of Herbalife, has made about $450 million in profits on the investment.

Ackman’s latest beef with Icahn—the two have been at odds for years, though seemed to call a truce two years ago on CNBC— stems from a statement Icahn released following Herbalife’s FTC announcement. In the statement Icahn declared that the FTC “concluded that Herbalife is not a pyramid scheme”—a statement that the FTC later disputed as “inaccurate.” In fact, the FTC did not explicitly conclude Herbalife was or wasn’t a pyramid scheme, with chairwoman Edith Ramirez saying only, “They were not determined not to be a pyramid.” That nuance has led to disagreement among Herbalife bulls and bears about what the FTC’s findings really mean.

“You have the CEO of a public company and a controlling shareholder misleading the public and you can see the impact—the 22% rise in the stock price on the public being misled,” Ackman said on hedge fund Pershing Square’s quarterly conference call Wednesday, referring to Herbalife CEO Michael Johnson and Icahn. “They’re trying to manipulate the stock price higher.”

In announcing the settlement with the FTC, Herbalife also said it had agreed to let Icahn increase his ownership stake in the company to nearly 35%. But Ackman dismissed this as a trick too. “I don’t think Carl Icahn intends to acquire more Herbalife stock or go up to 35%,” Ackman said. “I think this is part, frankly, of the manipulation.”

Ackman predicted the Securities and Exchange Commission would likely investigate the matter. “I bet there are emails, documents” showing a coordinated plan to mislead the media and market, Ackman said.

Ackman’s predictions for what regulators might do has not been great, particularly when it comes to Herbalife. Back in late 2012, he predicted that regulators would shut down the company. Last year, at a conference, Ackman said that executives of Herbalife were hiring criminal defense lawyers implying that they would soon be charged with a crime. Neither of those things ever happened.

Icahn did not immediately respond to a request for comment, but defended his statements about the FTC-Herbalife settlement in an interview with Fortune earlier this week: “If the FTC thought we were a pyramid scheme, in my opinion they would have not settled; they would have tried to shut us down,” he said. In the controversial statement itself, Icahn addressed his accuser—and longtime rival—by name, saying, “While Bill Ackman and I are on friendly terms, we have agreed to disagree (vehemently) on this subject.” (People hired by Ackman’s fund have previously been investigated for manipulating Herbalife stock in the other direction, but no charges have come of it.)

Herbalife, for its part, offered a statement responding to Ackman’s new allegations:

After more than two years of working with the FTC, I think we understand the terms of the settlement agreement very well. We would not have settled unless we had the greatest confidence in our ability to comply with the agreement and grow our business and we believe this will be proven out over time.

Shares of Herbalife were flat Wednesday afternoon.

This story has been updated to more accurately describe the Herbalife stock manipulation investigation relating to Ackman’s hedge fund. The investigation did not target Ackman himself, but rather contractors hired by his firm Pershing Square.