The shortcomings and potential dangers of international financial flows for the health and stability of domestic banking systems in developing countries have been copiously discussed over the last decades. While the importance of capital controls and regulation as determining factors has been widely emphasised, the extent to which these policies work in episodes of financial crisis is still a matter of debate. This article examines the relationship between supervisory frameworks and banking fragility in Mexico and Brazil in the wake of the international debt crisis of 1982. It shows that the model of international banking intermediation that evolved out of the stringent capital mobility system in Brazil was considerably less vulnerable to crisis than in Mexico, which had a more lightly regulated regime. These findings provide insights into historical debates about the implications of prudential regulation and capital controls for the development and expansion of foreign finance, and whether the risks underlying international banking are necessarily inherent in the process of financial globalisation.