Invalid economic assumptions
Robert Samuelson: ... It was once believed that the crisis of "subprime" mortgages -- loans to weaker borrowers -- would be limited, because these loans represent only 12 percent of all home mortgages. Even better, they were widely held, diluting losses to individual banks and investors. Wrong. Subprime mortgage losses (20 percent are delinquent) triggered a full-blown financial crisis. Confidence evaporated, because subprime loans were embedded in complex securities whose values and ownership were hard to determine. Similar doubts afflicted other bonds. Demand for all these securities shriveled. Lenders hoarded cash and favored safe U.S. Treasuries. Because investment banks and others relied on short-term debt (a.k.a. "leverage"), a loss of confidence and credit threatened failure. Lehman Brothers failed. The financial system had overborrowed and underestimated risk. It was once believed that American consumers could borrow and spend more, because higher home v...