upside down
adj.— «A growing number of motorists now find they owe more on their car loans than the vehicles are worth. The phenomenon, known as being “upside down” on a loan, reflects changes in the ways Americans buy and finance their vehicles.» —“More car buyers getting ‘upside down’ on car loans” Daytona Beach News-Journal (Florida) Apr. 16, 2005. (source: Double-Tongued Dictionary)