Abstract

ABSTRACT Asset‐market bubbles occur dependably in laboratory experiments and almost as reliably throughout economic history—yet they do not usually bring the global economy to its knees. The Crash of 2008 was caused by the bursting of a housing bubble of unusual size that was fed by a massive expansion of mortgage credit—facilitated, in turn, by the longest sustained expansionary monetary policy of the past half century. Much of this mortgage credit was extended to people with little net wealth who made slender down payments, so that when the bubble burst and housing prices declined, their losses quickly exceeded their equity. These losses were transmitted to the financial system—including banks, investment banks, insurance companies, and the institutional and private investors who provided liquidity to the mortgage market through structured securities. It seems that many of these institutions became insolvent; it is certain that they became illiquid. Liquidity loss and solvency fears created a feedback cycle of diminished financing, reduced housing demand, falling housing prices, more borrower losses, and further damage to the financial system and eventually the stock market and the real economy. There are important parallels with the housing and financial‐market booms that led up to the Crash of 1929 and the Great Depression.