In 2009, after the residential mortgage market had pretty clearly collapsed, people began worrying about commercial mortgages. Although bad subprime mortgages were responsible for popping the housing bubble, it continued to rapidly deflate when prime mortgages also began to default as the recession deepened and unemployment grew. Those same recessionary pressures began weighing on businesses, so some hypothesized that a commercial mortgage market collapse might be next. Delinquencies began risin...