Multiproduct Firms, Consumer Search, and Demand Heterogeneity

This study constructs a consumer search model in which some consumers search for multiple products, whereas others search for a single product. A price difference arises because of a difference in the price elasticity for each group. We show that a positive demand shock to one of the products decreases the price of another product, whereas it increases its own price, and a negative correlation between the demands for each product strengthens these tendencies. Both prices decrease, however, following a positive demand shock when the demands for each product are positively correlated. We also show that multiproduct firms set a relatively high price for a more demanded product, as such a product's price tends to be more elastic with respect to search costs. A price difference between products increases as the demand gap between products increases or as economies of scale in search increase.