Search Costs, Demand-Side Economies and the Incentives to Merge under Bertrand Competition

Abstract

This paper studies the incentives to merge in a Bertrand competition model where firms sell differentiated products and consumers search for satisfactory deals. In the pre-merger symmetric equilibrium, the probability that a firm is the next one to be visited by a consumer is equal across firms not yet visited. However, in the short-run after a merger, because insiders raise their prices more than what the outsiders do, consumers start searching for good deals at the non-merging stores. Only when they do not find any product satisfactory enough, they continue searching at the merging stores. When search costs are sufficiently large, consumer traffic from the non-merging firms to the merged ones is so small that mergers become unprofitable. This new merger paradox, which is more likely the higher the number of non-merging firms, can be overcome in the mediumto long-run if the merging firms choose to stock their shelves with all the products of the constituent firms, which generates sizable search economies. Such demand-side economies can confer the merging firms a prominent position in the marketplace, in which case their price may even be lower than the price of the outsiders. In that case, consumers visit first the merged entity and the firms outside the merger lose out. Search cost economies may render a merger beneficial for consumers and so overall welfare may increase. Keywords: mergers, insiders, outsiders, short-run, long-run, consumer search, demand-side economies, economies of search, order of search, sequential search, prominence