A major change has taken place in the company structure of the European electricity and gas markets. Since the liberalization of EU energy markets began in the 1990s, companies like E.ON, GDF Suez, EDF, Enel, and RWE have become European giants with activities in a large number of member states. The advocates of market liberalization did not expect, or intend, the emergence of a small number of large utilities that control an increasing part of the EU market. Some observers claim that liberalization has led to an oligopoly with detrimental consequences for competition. Based on extensive background research, this book presents a fact-based analysis of the changes in the European utility sector since the 1990s. Case studies of the seven largest utilities illustrate how companies adapted their strategies to the changing market environment. The author underlines diverging choices and common trends with the aim of using synergies between electricity and gas.