Abstract: This chapter examines the impact of private and public enforcement of securities regulation on the development of capital markets. After a review of the literature, it considers empirical findings related to private and public enforcement as measured by formal indices and resources, with particular emphasis on the link between enforcement intensity and technical measures of financial market performance. It then analyses the impact of cross-border flows of capital, valuation effects, and cross-listing decisions by corporate issuers before turning to a discussion of whether countries that dedicate more resources to regulatory reform behave differently in some areas of market activities. It also explores the enforcement of banking regulation and its relationship to financial stability and concludes by focusing on direct and indirect, resource-based evidence on the efficacy of the US Securities and Exchange Commission’s enforcement actions.