Anticompetitive mergers benefit competitors more than the merging firms. We show that such externalities reduce firms' incentives to merge (a holdup mechanism). Firms delay merger proposals, thereby foregoing valuable profits and hoping other firms will merge instead - a war of attrition. The...

Anticompetitive mergers increase competitors' profits, since they reduce competition. Using a model of endogenous mergers, we show that such mergers nevertheless may reduce the competitors' share-prices. Thus, event-studies can not detect anti-competitive mergers.

We demonstrate a 'preemptive merger mechanism' which may explain the empirical puzzle why mergers reduce profits, and raise share prices. A merger may confer strong negative externalilties on the firms outside the merger. If being an 'insider' is better than being an 'outsider', firms may merge...