Public Utility Regulation in the US and Asymmetric Return Responses to Positive and Negative Abnormal Earnings

This article focuses on regulation and variation in rate structures to investigate asymmetric return responses to positive and negative abnormal earnings. The abnormal earnings (AE) metric is measured as the difference between the actual profit rate and the maximum allowed profit rate, scaled by the beginning-period price. The analysis is motivated by the anticipated asymmetry in the information contents of positive and negative AE induced by existing rate structures which permit utilities to recover below normal profits but allow them to retain abnormal profits. Accordingly, negative AE is expected to be largely transitory and price-irrelevant whereas positive AE is expected to persist and be price-relevant. The results reveal significant asymmetry in return responses to positive and negative AEs. Specifically, the magnitude of return responses is larger for positive than for negative AEs. The results further show variations in the magnitudes of price responses across regulatory struture