The reselling of pre-owned jets is big business right now, with depreciation values reaching as much as 30% on year of use, particularly in Brazil, where the private aviation market surged by 76% between 2008 and 2010 (according to the National Civil Aviation Agency (ANAC), the Brazilian civil aviation authority), totalling 652 private jets and helicopters legally registered within the agency.

FORBES: Embraer Jet With A Tainted History Offers Steep Discount

Recent, grievous depreciation of stock values imperils the viability of one or more of even these giant concerns.

CENTERFORSECURITYPOLICY: Will Bush Team End the Ongoing Defense Fire Sale��?

While home values are still down on a year-over-year basis, the pace of depreciation has slowed dramatically since the start of this year.

FORBES: By Dr. Stan Humphries, Zillow Chief Economist