This research examines the changing relationship between states and markets in the provision of social protection. It provides empirical evidence of the differences in the ways governments are redefining the boundary between public and private mechanisms for social protection, and offers various explanations for the patterns revealed therein. In particular, the objective of this research is to discover more precisely how different combinations of political, social and economic factors shape national responses to the task of reforming public pension institutions in the context of strong market pressures. The study brings together a quantitative analysis of broad patterns of variation in the reforms throughout the world, with closer analysis of the complex and interconnected factors shaping the cases of Brazil and Mexico. The lessons drawn from this research should bring light to the dilemmas that may be encountered in countries that are currently undergoing this difficult task of renegotiating the social contract.