What happened

Shares of government IT contractor Booz Allen Hamilton (NYSE:BAH) closed down 19% on Friday.

So what

After close of trading Thursday, Booz Allen revealed that for more than a week it's been aware of an investigation into its business practices conducted by the U.S. Department of Justice. On June 7, said Booz, it received notification from the DOJ that it is "conducting a civil and criminal investigation" into its wholly owned subsidiary Booz Allen Hamilton Inc. "relating to certain elements of the Company's cost accounting and indirect cost charging practices with the U.S. government."

In other words, it's being investigated for accounting fraud.

Booz told investors that, so far as it can tell, "internal and external audit processes have not identified any significant deficiencies or material weaknesses, or identified any significant erroneous cost charging." Booz is cooperating with the government's investigation.

A stock chart falls through floor.

Hey! What just happened to Booz Allen Hamilton stock? Image source: Getty Images.

Now what

At 19 times earnings (after the sell-off) Booz stock still isn't particularly cheap. Analysts who follow the stock see Booz Allen Hamilton growing its earnings no faster than 9% annually over the next five years, and the stock pays only a 1.7% dividend yield (which is below average for the S&P 500).

Despite Friday's sell-off, I don't see any compelling need to rush out and buy the stock at its "new and improved" price -- because Booz is still no bargain.