Brazilian policymakers attempted to counter the inherent tendency for concentration in subsidized rural credit programs by requiring banks to lend a specified volume to small farmers. Inferences about the regulation's success are drawn from farm-level, panel data from São Paulo in the early 1980s. Membership in the target group should have a positive effect in an ‘access rule’, relating farmers' characteristics to their probability of receiving credit. When allowing for time-invariant individual effects, possibly correlated with target group indicators, tests indicate that the regulation had no effect. Subsidiary results cast doubt on the efficacy of a broader set of regulations.