Coordination Economies, Advertising, and Search Behavior in Retail Markets

We introduce a model of the retail firm in which consumers and active firms benefit collectively from coordination of sales at fewer firms. Using this model, we show that ostensibly uninformative advertising plays a key role in bringing about coordination economies, by directing consumer search toward firms that offer the best deals. Optimal consumer search takes the form of a simple rule of thumb that uses observed advertising information to guide search. Both industry concentration and social surplus are higher in the presence of advertising, relative to a no-advertising benchmark.