In the 1980s, Chile adopted a mixed (public and private) model for health insurance coverage similar to the one recently outlined by the Affordable Care Act in the United States (US). In such a system, a mix of public and private health plans offer nearly universal coverage using a combined approach of managed competition and subsidies for low‐income individuals. This paper uses a “most different” case study design to compare policies implemented in Chile and the US to address self‐selection into private insurance. We argue that the implementation of a mixed health insurance system in Chile without the appropriate regulations was complex, and it generated a series of inequities and perverse incentives. The comparison of Chile and the US healthcare reforms examines the different approaches that both countries have used to manage economic competition, address health insurance self‐selection and promote solidarity. Copyright © 2015 John Wiley & Sons, Ltd.