Since 2007, those most exposed to negative equity are borrowers who obtained loans of a high percentage of the property value (maybe 90% or even 100%).
This major and unexpected decline in house prices means that many borrowers have zero or negative equity in their homes, meaning their homes were worth less than their mortgages.
Many homeowners found themselves with negative equity meaning the mortgage balance was considerably higher than the market value of the home also known as being underwater.