The ''portfolio effect theory'' developed by the European Commission in merger control is at the center of a fierce international row with the US authorities who believe that this theory has no economic foundations. This paper aims to provide a counter-argument and shows that full-line forcing...

A supplier is known to be subject to opportunism when contracting secretly with downstream competitors, particularly when downstream firms have "passive beliefs." We stress that in many situations, an equilibrium with passive beliefs may not exist and passive beliefs appear less plausible than...

Frauds can be explained not only in terms of individual willingness to cheat, but may also be driven by opportunities to behave dishonestly. The audit policy should therefore be different for different categories of agents. This paper focuses on the optimal audit policy when there are two...

Using a unique dataset merging micro data at product and store level with data on competition within local grocery markets, this paper provides an empirical analysis of a legislation that had the same effect as allowing industry-wide price floors. It shows that, after the introduction of the...

We study information transmission between an informed expert and an uninformed decision-maker when the decision is binary and the expert does not have a systematic bias. Whenever, an equilibrium exists where the decision is delegated to the expert, it is ex-ante Pareto-dominant. Adding a round...

Council Regulation (EC) 1/2003 came into force in May 2004 and replaced the mandatory notification of agreements by a regime of ex post monitoring. This paper shows that ex post monitoring is the optimal audit regime when the competition authority's probability of error is low. On the other...

We study information transmission between an informed expert and an uninformed decision-maker when the decision is binary and the expert does not have a systematic bias. Whenever an equilibrium exists where the decision is delegated to the expert, it is ex ante Pareto-dominant. Adding a round of...

The European Commission recently considered abolishing the notification system and to focus on a regime of ex post investigation. Our objective is to show that a better understanding of markets can justify this reform. When the precision of the competition authority?s analysis is not high...