Abstract :
The purpose of this study to investigate the effect of merger and acquisition of abnormal stock returns . Type of research is the study of events with the estimation period of 20 days and the event period of 10 days before and after the merger . The sample used in this study were 24 company listed on the BEI in the period 2013-2015 with the research method of comparative studies using parametric test One Sample T
Test and Paired Sample T - Test to answer the hypothesis . The test results showed
negative influence around the date of the acquisition announcement , in other words,
the market reaction tends to be negative on acquisitions that occurred . The positive
effects occurred long before the announcement date of acquisition resulting
information already known in advance by the market , it demonstrates the capital
market in Indonesia has not fulfilled an efficient capital market assumptions
Keywords: acquisition, merger, abnormal return, stocks, efficient