All it takes to wipe out the bank’s own money is a 16% drop in the house’s price (from $235,000 to below $198,000). US house prices – as measured by the S&P/Case-Shiller National Home Price Index – fell by more than 30% from June 2006 to March 2009, while European countries, including Spain, Ireland, and the United Kingdom, experienced similar or greater declines.