Hold-up of anti-competitive mergers

We construct a model of endogenous mergers and study some issues of whether and how to control mergers, taking into account firms equilibrium response to policy. Anti-competitive mergers benefit competitors more than the merging firms. We show how such free-riding reduces firms incentives to merge (holdup). Firms delay merger proposals, hoping other firms will merge instead. The final result, however, is an overly concentrated market. Merger control may thus preserve competitive markets. In the presence of holdup, even reasonable policies such as requiring divestiture or using cost-benefit analysis, may be worse than not controlling mergers at all.