Supersize It - The Growth of Retail Chains and the Rise of the "Big Box" Retail Format

We offer a theory for the complementarity between the size of a retail chain and the scope of its business to explain the growth of general-merchandise firms and the expansion of the "superstore" format. The complementarity results from an interaction of the retailer's economies of scale and consumer gains from "one-stop shopping." We find support for our model in micro data from the Census of Retail Trade for 1977-2002. Retail chains with more stores carry more distinct product lines and as retail chains grow they add both stores and product lines. On average, we find that a chain adds one product line, such as shoes, computers, or jewelry, to an existing store with every new store it opens. For the average large chain, adding a new product line throughout the chain is correlated with adding 400 new stores, competing in over 8,000 new markets and increasing its competitive pressure in more than 10,000 additional markets.