Multidivisional firms, internal competition, and the merger paradox

Abstract.  Traditional modelling of mergers has the merged firms (insiders) cooperate and maximize joint profits. This approach has several unappealing results in quantity‐setting games, for example, mergers typically are not profitable for insiders, but are profitable for non‐merging firms (outsiders). We take a different approach and allow for a parent company that can play each insider off one another. In quantity‐setting games, with our approach mergers are profitable for insiders, unprofitable for outsiders, socially beneficial, and involve (in a non‐monopolizing merger) a small number of firms. Finally, we find that the optimal strategy depends on whether firms compete in quantity or prices. JEL classification: L000