The informational consequences of good and bad mergers

We study the information production dynamics in financial markets in response to Mergers and Acquisitions (M&As) announcements. We find that acquirers with low levels of pre-announcement stock price informativeness experience a substantial increase in their corresponding post-announcement stock price informativeness in response to positive Cumulative Abnormal Returns (CAR). We show that this increase is due to the enhanced prospect of deal completion. By contrast, high levels of acquirer pre-announcement stock price informativeness limit traders' incentives to search for, and acquire, new information. We also find that similar dynamics apply to the changes in acquirers' analyst coverage. Emphasizing the important role of information acquisition costs in influencing informed trading, a positive acquirer CAR increases the acquiring firm's post-announcement stock price informativeness in M&As involving public rather than private and subsidiary targets. Overall, we show that M&As have important informational consequences beyond their immediate effects on stock prices.