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Bill Ackman to unveil new Herbalife information: Source

Ackman to take on Herbalife again

Activist investor Bill Ackman is preparing another major presentation on Herbalife, a source told CNBC on Thursday.

The presentation, set to be made at the Robin Hood Investment Conference in November, will include new information that his firm, Pershing Square, has uncovered after speaking with several former employees of the company, according to the source.

Ackman revealed his $1 billion short position in the company at an Ira Sohn Conference last December, calling the company's business model "a pyramid scheme."

Herbalife up after earnings

Since then, billionaire investor Carl Icahn took the other side of Ackman's short, and the two famously battled on CNBC's "Halftime Report" in late January, with Icahn saying the whole thing would end with what he called, "the mother of all short squeezes."

(Read more: Bill Ackman, Carl Icahn hurl accusations, insults)

Herbalife shares have nearly doubled this year.

Ackman who has lost millions on the short bet, restructured it last month to cut the risk of being caught in a squeeze.

Bill Ackman
David Grogan | CNBC

But apparently his conviction hasn't changed, as he continues to assail the company's business practices in several letters to Pershing Square's investors. In late August, he wrote directly to Herbalife's new auditor, PricewaterhouseCoopers, detailing what he called "serious accounting issues."

(Read more: Ackman to PwC: Herbalife may get you in trouble)

Herbalife has said it "stands by its prior financial statements."

Herbalife continues to post strong earnings and has made a couple of high-profile board appointments.

(Read more: Carl Icahn finally has some good to say about Bill Ackman)

But Ackman and other shorts clearly feel some issues remain unresolved.

Investors are still waiting for the company to receive its audited financials and will now be left to wonder what Ackman has up his sleeve next.

—By CNBC's Scott Wapner. Follow him on Twitter: @ScottWapnerCNBC.