We have two upstream firms producing each one a different good. Demands of the goods are independent, symmetric and linear. Goods are sold to consumers through retailers. The units of both goods sold by retailers cannot exceed the industry selling capacity that it is distributed symmetrically among retailers. Taking as given the industry selling capacity, when the number of retailers decreases, they become bigger in the sense that their selling capacity increases. Therefore, changing the number of retailers, we can check whether the countervailing power theory, that states that bigger retailers obtain better deals from suppliers, holds in our model. We obtain that the lower the number of retailers, the lower the wholesale prices, only when the industry selling capacity is high.I acknowledge financial support from the Spanish Ministerio de Economía y Competitividad and FEDER funds ECO2015-65820-P (MINECO/FEDER) and from Generalitat Valenciana grant PROMETEO/2019/037
