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...

In a framework where mergers are mutually excluding, I show that firms pursue anti- rather than (alternative) pro-competitive mergers. Potential outsiders to anti-competitive mergers refrain from pursuing pro-competitive mergers if the positive externalities from anti-competitive mergers are...

This paper tests the insiders' dilemma hypothesis in a laboratory experiment. The insiders' dilemma means that a profitable merger does not occur, because it is even more profitable for each firm to unilaterally stand as an outsider (Kamien and Zang, 1990 and 1993). The experimental data...

The purpose of this report is to contribute to the analysis of two questions. Should a merger control system take into account efficiency gains from horizontal mergers, and balance these gains against the anti-competitive effects of mergers? If so, how should a system be designed to account for...