The 2008 wave of goodwill impairments provides yet another disturbing piece evidence of the value that’s being wrung out of companies as a result of the recession.

Goodwill is an intangible asset that often results from an acquisition; it’s the amount a company pays to acquire another company over and above the fair value of the individual net assets that are acquired. Accounting rules require companies to test or verify the value of goodwill at least annually; it must be written down if it is impaired, or if the value has eroded.

A recent KPMG study of four years worth of financial data for more than 1,600 U.S.-based companies shows goodwill impairment more than doubled in 2008 from 2007. KPMG says that goodwill impairment charges for the companies studied rose to $340 billion in 2008, more than double the $143 billion recorded in 2007 and nearly four times the $87 billion reported in 2006.

Banks, of course, took the biggest hit to goodwill. They accounted for almost 23 percent of the total goodwill impairment charges in the KPMG study, followed by materials, energy, media and technology hardware and equipment, pharmaceuticals, and food and beverages.

Seth Palatnik, a partner in valuation services for KPMG, said companies can thank turmoil in financial markets for the recent hits to goodwill, which cause non-cash charges to earnings and markdowns in the asset and equity sections of the balance sheet. “Goodwill impairment charges increased significantly at the end of 2008, in part, due to the fact that many companies’ December fiscal year-end coincided with their annual goodwill testing procedure,” he said.

The overall market slide that began in the fall of 2008 also had a material impact on the rise in year-end goodwill impairments, Palatnik said. “As part of this process, companies needed to consider whether recent economic events such as stock prices falling below carrying value on the books resulted in goodwill impairments,” he said.

Greg Franceschi, managing director at financial advisory and investment banking firm Duff & Phelps, said companies should expect to face much less impairment testing at the end of 2009. “Mark values have rebounded quite a bit since the lows of last year,” he said. “The economic trends at this point are much more certain than they were in the middle of last year. The general consensus is we’ve probably hit the floor in terms of economic lows. That means values are probably higher than last year.”