Under what conditions can opposition politicians with ethnic constituencies form electoral coalitions? In Africa’s patronage-based political systems, incumbents form coalitions by using state resources to secure the endorsement of politicians from other ethnic groups. Opposition politicians, however, must rely on private resources to do the same. This article presents a political economy theory to explain how the relative autonomy of business from state-controlled capital influences the formation of multiethnic opposition coalitions. It shows that the opposition is unlikely to coalesce across ethnic cleavages where incumbents use their influence over banking and credit to command the political allegiance of business—the largest potential funder of opposition in poor countries. Liberalizing financial reforms, in freeing business to diversify political contributions without fear of reprisal, enable opposition politicians to access the resources needed to mimic the incumbent’s pecuniary coalition-building strategy. A binomial logistic regression analysis of executive elections held across Africa between 1990 and 2005 corroborates the theoretical claim: greater financial autonomy for business—as proxied by the number of commercial banks and the provision of credit to the private sector—significantly increases the likelihood of multiethnic opposition coalitions being formed.