Collusion sustainability depends on firms' aptitude to impose sufficiently severe punishments in case of deviation from the collusive rule. We characterize the ability of oligopolistic firms to implement a collusive strategy when their ability to punish deviations over one or several periods...

We consider an optimal portfolio diversification model in which a large shareholder can influence shares return by monitoring efficiently managers. Less diversification decreases insurance but increases the stake in the ownership and then enhances efficiency of management monitoring. We analyze...

This paper considers a model of two interconnected networks with different qualities. There are call externalities in the sense that consumers value calls they send and receive. Networks compete in two part tariffs. We show that call externalities create private incentives for each competitor to...

Cet article tente d'expliquer l'impact ambigu de la loi Raffarin sur les relations entre producteurs et distributeurs, en montrant qu'elle exerce deux effets opposés sur le partage du profit entre les secteurs amont et aval. Nous proposons un modèle permettant d'appréhender l'influence d'une...

We discuss Shen and Starr(2002) results and show that the bid-ask spread of a monopolistic market-marker doesn't depend on his inventory when he posts ''martingale prices '' in an inventory model with random volumes and an unknown direction of trade.