There is an urgent need to understand why many households in the US do not hold a bank account. This column argues that supply-side factors – standard bank practices that ration certain households – play a role in this. The evidence comes from the staggered interstate branching deregulation after 1994 that provides an exogenous shock on bank competition. Further findings suggest that access to bank accounts improves access to credit without translating into higher ratios of debt to income.