Updated from 8:54 a.m. EDT
NEW YORK (TheStreet) -- Shares of Herbalife (HLF - Get Report) jumped 6% in early trading on Friday on news that people affiliated with the company's chief antagonist and activist investor Bill Ackman are being questioned as part of a federal criminal probe into potential market manipulation of Herbalife's stock.
According to a report in The Wall Street Journal, the Federal Bureau of Investigation and prosecutors with the Manhattan U.S. Attorney's office have interviewed and requested documents from people Ackman hired to lobby regulators against the maker of nutritional supplements.
The investigation is focused on "whether people, including some hired by Mr. Ackman, made false statements about Herbalife's business model to regulators and others in order to spur investigations into the company and lower its stock price," according to the Journal.
Regulators are reportedly combing through public statements and allegations that these individuals made regarding Herbalife and are looking into whether any potential connection or collaboration occurred between these individuals and Ackman's hedge fund Pershing Square Capital Management, the Journal reports. Ackman, as well as his firm, have not received a subpoena or a visit from FBI agents in regard to the probe.
The criminal probe turns the table on Ackman's assault of Herbalife over the past two years. Ackman alleges the company operates a pyramid scheme and backed it up with a $1 billion bet that Herbalife's stock will fall.
The Federal Trade Commission has investigated the pyramid scheme allegations for more than a year, while the Securities and Exchange Commission is looking into whether Herbalife's business operations violates any SEC laws.
In a statement to the Journal, a Pershing Square spokesman said, "We have been completely transparent about our position and our research, and we have acted lawfully in every respect."
Ackman told CNBC on Friday that he hasn't traded around his short position in Herbalife.
"We're not trying to make money on short-term moves in Herbalife stock," Ackman told CNBC's "Squawk Box."
"Any one at the government is welcome to look at how we traded this," Ackman said.
Herbalife also weighed in. "Mr. Ackman has a $1 billion bet against Herbalife and a direct financial interest in hurting our company. For more than two years, he has spent $75 million orchestrating a false and fabricated attack against Herbalife," Alan Hoffman, a company spokesman, said in a statement released late Thursday.
The stock rose 6% on Friday to $35.24 early Friday.
Meanwhile, Herbalife CEO Michael Johnson had his pay cut last year because he missed his performance targets.