This paper argues that the balance of power between producers and retailers
depends on the relative degrees of differentiation at the two levels of the
vertical structure. We propose an extension of Hotelling’s model in which
two producers, competing in prices with horizontally differentiated
products, face two horizontally differentiated retailers also competing in
prices. We study the setting of producers’ and retailers’ margins. We show
that when retailers are more differentiated than producers, they dominate
the relationship and their margin is higher than producers’.