In a model of monopolistic competition with heterogeneous firms, distortions in prices drive a wedge between the marginal revenue products of factor inputs across firms. We use census data for Brazil's retail sector to study implications for aggregate productivity and relate distortions to regional variation in regulation using a differences‐in‐differences approach. Taxes, entry regulation, and access to credit may create distortions to output and capital that varies by firm size. Potential gains from reallocation have not diminished despite the process of services liberalization in the 1990s.