The article reexamines financial market opening in Mexico. This article will show how change in Mexico's financial sector created a powerful private sector ally for reform-oriented politicians and helped make financial opening possible. It will also show how financial opening reflected the support coalition that the government relied upon by rewarding the financial sector with protection from foreign direct investment in financial institutions while liberalising portfolio capital flows. Finally, this article will illustrate the importance including an analysis of local financial sector interests in explanations of financial opening.