In the early 1980s Argentina, Brazil, and Mexico had commercial banking sectors that were dominated by local banks. The largest countries in Latin America were subjected to common international economic pressures during both the neoliberal 1980s and 1990s – including the expansion of capital markets in the periphery and integration into the regional trade agreements NAFTA and Mercosur – and the post-1998 financial turmoil. By 2015, however, the three countries had consolidated alternative commercial banking systems: domestic private group dominated (Brazil), mixed (i.e., ownership more evenly divided among public, private domestic, and foreign banks (Argentina), and foreign bank dominated (Mexico). The article traces these alternative outcomes to the power of prereform private financial groups, the virulence of “twin crises” in the transition from fixed to floating exchange rates, and the (contingent) role played by government ideology.