This chapter aims to collect and report cross-country data on bank regulation and ownership; and to evaluate the links between different regulatory/ownership practices and both financial sector performance and banking system stability. In so doing, it hopes to help fill the gap between the questions posed by policymakers about how to reform banking systems and the currently available evidence on the issue produced by researchers. The chapter examines the following questions: Firstly, do countries with regulations that impose tighter restrictions on the ability of commercial banks to engage in securities, insurance, and real estate activities have (a) less efficient but (b) more stable financial systems? Secondly, do countries that restrict the mixing of banking and commerce—both in terms of banks owning nonfinancial firms and nonfinancial firms owning banks—have (a) less efficient but (b) more stable banking systems? Thirdly, do countries in which state-owned banks play a large role have more poorly functioning financial systems? A commentary and discussion summary are also included at the end of the chapter.