Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Herbalife Ltd. (HLF 4.37%) were up 14.5% Friday as of noon, following news of an FBI investigation of whether noted short-seller and hedge fund manager Bill Ackman and his contractors manipulated the company's stock.

So what: Ackman, for his part, has long alleged Herbalife's multilevel marketing model is a "pyramid scheme" -- something Herbalife has adamantly denied -- and suggested the Federal Trade Commission will ultimately shut down the herbal supplement provider's business.

Late Thursday, however, The Wall Street Journal reported [subscription required] that both federal prosecutors and the Federal Bureau of Investigation have conducted interviews and sent document requests in recent months in an effort to determine whether Ackman or people hired by him made false statements about Herbalife to regulators in order to spur investigations into the company.

The Wall Street Journal also cited a "person familiar with the situation" as stating neither Ackman nor his fund, Pershing Square, have been served with a subpoena or visited by FBI agents in connection with the probe.

Now what: Ackman later echoed that statement, saying he hasn't been contacted by the FBI. But he did confirm one of his contractors -- Global Strategy Group, which handles government relations -- has been questioned, and its sub-contractors have received a subpoena.

Investors should keep in mind this investigation doesn't guarantee there was any wrongdoing. Ackman also unsurprisingly insisted he has nothing to hide, and simultaneously repeated his allegations against Herbalife. In the end, considering this battle is far from over and could go either way, I'm still perfectly content watching the drama unfold from the sidelines.