Financial innovation, the discovery of risk, and the U.S. credit crisis2010

"Uncertainty about the riskiness of a new financial environment was an important factor behind the U.S. credit crisis. We show that a boom-bust cycle in debt, asset prices and consumption characterizes the equilibrium dynamics of a model with a collateral constraint in which agents learn "by observation" the true riskiness of the new environment. Early realizations of states with high ability to leverage assets into debt turn agents overly optimistic about the probability of persistence of a high-leverage regime. Conversely, the first realization of the low-leverage state turns agents unduly pessimistic about future credit prospects. These effects interact with the Fisherian deflation mechanism, resulting in changes in debt, leverage, and asset prices larger than predicted under...