Differences in Differentiation : Rising Variety and Markups in Retail Food Stores

In this paper I show that consumers in food stores and supermarkets/hypermarkets became significantly less price sensitive between 2006 and 2017. At the median, across thousands of stores and products in nine large categories, estimated own-price elasticities have declined by 25% over this period. I argue that these changes are likely due in part to improved supply chain management, which has led stores to offer a larger variety of goods which better match consumers’ individual preferences. I show that newer products are indeed more “niche” in this sense, and that other potential sources of rising differentiation including increases in quality and changes in consumer wealth play a smaller role. Markups implied by a monopolistic pricing rule suggest that the observed rise in differentiation was large enough to generate significant increases in firms’ markups absent any changes in pricing behavior or competition