This article analyzes the performance of foreign electric-utility companies and the evolution of the electric-power industry in Argentina from 1890 until the end of the 1950s, when the electric utilities were nationalized. It focuses on the decisions and strategies of the subsidiaries controlled by two holding companies: the Société Financière de Transports et d'Entreprises Industrielles (SOFINA) and the American & Foreign Power Company. The study suggests that the divergence in the performance of these two companies was determined both by their investment patterns and by their financial styles and management decisions. The impact of private decisions and public regulation on the Argentinean electric-power system is also explored.