The European liberalising electricity industries are still heavily regulated. A prominent form of regulation is directed at the energy companies' forms of governance. European and national regulations prohibit the vertically integrated structures that characterised these companies for almost a century. Detailed rules on unbundling, independence of the transmission and distribution system operators, and network access influence to a large extent the type of new governance structures that are adopted. This paper takes the institutional organisation of regulation into account to explain the regulatory influence on governance changes at the level of the firm. Examples of the Dutch and French electricity industries illustrate that the new forms of governance are heavily influenced by the institutional organisation of regulation. © 2006 The Authors. Journal compilation