Financial innovation, the discovery of risk, and the U.S. credit crisis

Financial innovation and overconfidence about the risk of new financial products were key factors behind the 2008 U.S. credit crisis. We show that a model with a collateral constraint in which learning about the risk of a new financial environment interacts with Fisherian amplification produces a boom-bust cycle in debt, asset prices and consumption. Early realizations of a high-borrowing-ability regime turn agents optimistic about the persistence probability of this regime. Conversely, the first realization of a low-borrowing-ability regime turns agents unduly pessimistic. The model predicts large increases in household debt, land prices and excess returns during 1998-2006 followed by a collapse.