We propose a model in which mergers exert a more pronounced effect on the structure of a market than simply reducing the number of competitors. We show that this may render horizontal mergers profitable and welfare-improving even if costs are linear. The results help to reconcile theory with...

The seminal paper by Salant, Switzer and Reynolds (1983) showed that merger in a standard Cournot framework with linear demand and linear costs is not profitable unless a large majority of the firms are involved in the merger. However, many strategic aspects matter for firm competition such as...