This book describes the value generated to the shareholders of acquiring companies by the announcement of mergers and acquisitions. Cumulative Abnormal Announcement Returns to those shareholders, due to the announcement of a merger or acquisition, reflect a possible revision of the expected value resulting from boosted economies of scale, future synergies or wealth redistribution among stakeholders. The author investigated how bidder returns dispersed in 168 acquisitions by Dutch companies, and whether or not this dispersion can be explained based upon nine explanatory variables, being Announcement date equals rumour date, Domestic or cross border acquisitions, Payment type, Industry similarity between bidder and target, Public or private target, Owner control in the bidding company, Relative size of the target, Bidder acquisition experience and Market timing. These variables serve as determinants, of which some prove to have a positive or negative influence on the CAAR. Some determinants however have (according to prior empirical research) a positive effect on the announcement share price. A must for all shareholders of acquiring firms acting as bidders in a takeover.