The deep recession the United States entered in 2007, sometimes described as the Great Recession, started with the deflation of a housing bubble. To understand what went wrong in the housing market, one has to understand the role of subprime mortgage lending—loans designed for borrowers with blemishes on their credit records. In 2005 and 2006, subprime mortgage loans made up 23 percent of all home loans written. Yet as recently as the mid-1990s, they were an insignificant share of the mortgage lending market.





