This paper examines the impact of multiple directorships on stockholder wealth around the announcements of mergers and acquisitions. Grounded in agency theory, we argue that multiple directorships affect the quality of managerial oversight and thus influence agency conflicts in acquisition decisions. We show that acquiring firms where directors hold more outside board seats experience more negative abnormal returns. This adverse effect, nonetheless, does not extend across the entire range of multiple directorships. Rather, the detrimental impact is significant only when the number of outside board seats surpasses a certain threshold. We interpret this result as suggesting that directors serving on multiple boards allow value-destroying acquisitions when they become too busy beyond a certain point, and the effect of directors’ busyness on acquisition performance appears to be nonlinear. We employ several alternative definitions of directors’ busyness and obtain consistent results.

Grounded in agency theory, this study investigates how the strength of shareholder rights influences the extent of firm diversification and the excess value attributable to diversification. The empirical evidence reveals that the strength of shareholder rights is inversely related to the probability to diversify. Furthermore, firms where shareholder rights are more suppressed by restrictive corporate governance suffer a deeper diversification discount. Specifically, we document a 1.1–1.4% decline in firm value for each additional governance provision imposed on shareholders. An explicit distinction is made between global and industrial diversification. Our results support agency theory as an explanation for the value reduction in diversified firms. The evidence in favor of agency theory appears to be more pronounced for industrial diversification than for global diversification.