The rise and fall of subprime mortgages

After booming the first half of this decade, U.S. housing activity has retrenched sharply. Single-family building permits have plunged 52 percent and existing-home sales have declined 30 percent since their September 2005 peaks. ; A rise in mortgage interest rates that began in the summer of 2005 contributed to the housing market's initial weakness. By late 2006, though, some signs pointed to renewed stability. They proved short-lived as loan-quality problems sparked a tightening of credit standards on mortgages, particularly for newer and riskier products. As lenders cut back, housing activity began to falter again in spring 2007, accompanied by additional rises in delinquencies and foreclosures. Late-summer financial-market turmoil prompted further toughening of mortgage credit standards. ; The recent boom-to-bust housing cycle raises important questions. Why did it occur, and what role did subprime lending play? How is the retrenchment in lending activity affecting housing markets, and will it end soon? Is the housing slowdown spilling over into the broader economy?