TITLE "Market Efficiency: Evidence from Market Reactions of Insurance Industry Stocks to the September 11, 2001 Event," Yuling Wang and Richard B. Corbett, Volume 31, pp 152-167.

ABSTRACT The events of September 11, 2001 had profound financial consequences for the insurance industry. Property and liability insurers took significant underwriting losses in many lines as a result of this event. Property and liability insurer stocks might then be expected to have higher negative abnormal returns than the stocks of life and health insurers. Using traditional event study methodology with a longer event window, we find that property and liability insurer stocks did generate much larger abnormal returns than those of life and health insurers. We also find that, after the first week of trading subsequent to the market’s reopening on September 17, the abnormal returns were not significant from zero, which is consistent with the efficient market hypothesis. Insurance industry stocks recovered quickly after the events of September 11 and sometimes even outperformed the market. Investors were rational and responded to the expectation of increases in insurance demand and strength in capacity constraints.