Catastrophic Events, Parameter Uncertainty and the Breakdown of Implicit Long-Term Contracting: The Case of Terrorism Insurance

This paper examines the reaction of the stock prices of U.S. property-casualty insurers to the World Trade Center (WTC) terrorist attack of September 11, 2001. Theories of insurance market equilibrium and theories of long-term contracting predict that large loss events which deplete capital and increase parameter uncertainty will affect weakly capitalized insurers more significantly than stronger firms. The empirical results are consistent with this prediction. Insurance stock prices generally declined following the WTC attack. However, the stock prices of insurers with strong financial ratings rebounded after the first post-event week, while those of weaker insurers did not, consistent with the flight-to-quality hypothesis.