How much are differences in managerial ability worth?

We identify manager/firm separations where managers quit for a new job and study abnormal returns associated with these events. Applying analyses from labor economics, we argue that the average ability of managers who resign for a similar position at another firm should be higher than that of manage rs who die suddenly. Controlling for age and tenure, we find that firms los ing managers to other firms experience an average abnormal return of -1.51% ; compared to +3.82% for firms whose managers die suddenly. We use differen ces in returns across groups to measure the value of differences in manager ial ability. (C) 1999 Elsevier Science B.V. All rights reserved. JEL classi fication: G30; J31; J41.