More on the Impact of the Three Mile Island Nuclear Accident on the Risk and Return of Electric Utilities

Abstract

The purpose of this paper is to examine the impact of the March 28, 1979 accident at the Three Mile Island (TMI) nuclear power facility on the risk and return of General Public Utilities (TMI's owner) and other electric utilities heavily invested in nuclear power facilities. The results have implications for the returns required by investors and, therefore, on the economic viability of nuclear power for electricity generation. A recent article by Bowen, Castanias, and Daley used cumulative abnormal residual (CAR) analysis to examine the impact of the TMI accident on the electric utility industry. However, as has been shown by Larcker, Gordon, and Pinches, CAR results may be misleading due to systematic risk changes and autocorrelation in the data. Intervention analysis is proposed as an alternative to CAR analysis. This paper compares the results of a traditional cumulative abnormal residual analysis with the results of intervention analysts. It is found that the CAR analysis indicates abnormal negative returns occurred immediately after the TMI accident. However, intervention analysis shows the assumptions necessary for the CAR method to be appropriate are violated. When adjustments are made for a shift in systematic risk and autocorrelation, no abnormal returns are observed for GPU, for other utilities with nuclear facilities or for non‐nuclear utilities. These results are in conflict with those reported by BCD.

Citation

CHEN, K.C., LINKE, C.M. and KENTON ZUMWALT, J. (1986), "More on the Impact of the Three Mile Island Nuclear Accident on the Risk and Return of Electric Utilities", Managerial Finance, Vol. 12 No. 4, pp. 4-8. https://doi.org/10.1108/eb013571