Less than two years after Michael Baker Corp. [Ticker: BKR] cleaned up accounting problems that forced it to restate results as far back as 2001, management of the Moon engineering and energy services firm has discovered new problems with the company's bookkeeping.

The revelation has battered Baker's shares, which rose 81 percent last year on reports of the sale of the energy business and a potential merger or acquisition. They finished 2007 at $41.10.

Since the latest accounting issues were announced Feb. 22, Baker shares have fallen 24 percent. They closed Friday at $27.50, down 33 percent on the year.

Baker says it will have to restate earnings for the first nine months of last year. The company said the non-cash errors are related to improper revenue recognition for several domestic energy projects. Fixing the errors may erase the $12.5 million in operating income Baker previously said the energy business earned in the first three quarters, a number that does not include corporate overhead.

The company previously reported net income for the nine months of $18 million, or $2.03 per share.

In a filing with the Securities and Exchange Commission, Baker said it was evaluating whether it would have to restate its 2006 results because of the errors. The audit committee is launching an independent investigation of the matter.

Baker's previous accounting miscues were disclosed in August 2005, when it warned it would have to restate earnings because of accounting discrepancies dealing with its Nigerian energy operations and insurance. Those mistakes were cleared up a year later, with Baker paying $1.8 million in 2006 for professional fees related to the restatement.

Spokesman David Higie declined to provide any estimate of how long it will take to resolve the matter, whether the company's fourth-quarter results will be filed on time, and whether the accounting issue affects the proposed sale of the energy business.

"We will make further public announcements as information becomes available," he said in an e-mail.

There is an average of seven weeks between the time a publicly traded company discloses it has to restate earnings and the time it actually does so, according to a study conducted by Huron Consulting Group. The Chicago-based consulting firm studied about 1,900 statements announced between August 2004 and December 2006 and found that in 79 percent of the cases, the accounting was cleared up within four months. About 15 percent took longer than eight months to resolve, Huron discovered.

In 19 percent of the cases, companies ended up fixing more mistakes than were initially disclosed, Huron said.

The day before the disclosure, Baker announced it was beefing up the accounting experience on its board, electing Duquesne Light Holdings Chief Financial Officer Mark E. Kaplan as a director. The company simultaneously named Bradley L. Mallory president and chief executive officer. Mr. Mallory, Pennsylvania's former transportation secretary, joined Baker in 2003.

Another local stock moving in the wrong direction is Mylan [MYL]. Shares of the Cecil generic drug maker have declined 19 percent since the company posted a $1.38 billion fiscal third-quarter loss after the market closed Feb. 27. They traded as cheap as $10.04 Friday before closing at $10.60, off $1.24 for the week. They haven't closed that low since March 2001, according to an analysis of Bloomberg data.

Much of the recent decline stems from Wall Street's uncertainty over Mylan's future. The company says it won't provide guidance until May. There also are concerns about whether Mylan will be able to manage its $6.8 billion purchase of Merck KGaA's generic unit in October. Mylan shares were trading at $22.40 when the acquisition was announced in May.

"Management continues to confuse investors in the way it discusses its performance and guidance, which continues to foster a management credibility issue," Credit Suisse analyst Marc Goodman said in a note to investors.

Chief Executive Officer Robert J. Coury has brushed aside those worries, telling analysts during a recent conference call that, "Our strategy is not only sound, but on track, and we are extremely pleased with this acquisition.

"All of the growth we have promised you is right here at our fingertips," he said.

Mr. Coury backed up his words last week, purchasing 45,000 shares over the course of three days, according to Securities and Exchange Commissions filings.

He purchased 15,000 shares at $10.91 per share on Wednesday, 10,000 more on Thursday at $10.74 per share, and finished the week by purchasing 20,000 shares at $10.14 on Friday. The purchases increased Mr. Coury's holdings to 576,149, including 281,628 shares of restricted stock. That's about 0.1 percent of Mylan shares outstanding.