Merger and acquisitions has increased rapidly the last three decades. There has been a lot of articles discussing the wealth created for shareholders. Most articles are focusing on how the returns are changing for the targeted firms after the announcement of a takeover. In this thesis I have been investigating the abnormal return for the acquiring firm when announcing for a takeover. With data of stock prices collected from DataStream and Eikon, I have performed an event study. The findings indicate that a Swedish firm listed on the stock market on average have a negative abnormal return when announcing for a takeover of another firm.