Cet article s'attache à donner des fondements théoriques à la structure verticale des réseaux de distribution des drogues illicites, en faisant appel à l'analyse des relations verticales et en intégrant le caractère illégal de cette activité. Il analyse ensuite la manière dont les autorités, par l'intermédiaire des coûts de répression qu'elles imposent aux vendeurs de drogues, peuvent mettre en œuvre dans le cadre d'un équilibre décentralisé l'optimum social. Nous montrons qu'un réseau verticalement séparé, structure optimale de premier rang, très couramment observée sur ce marché, ne peut jamais être mis en œuvre.

A benevolent social planner, which faces a cost of public funds because of distortive taxation, wants to finance an upstream monopoly. This monopoly produces a necessary input for a downstream competitive sector which competes á la Cournot (with either a fixed number of firms or free entry in the downstream sector). We show that in both cases an ad valorem access charge is a better regulatory tool than a per unit access charge if the access charges are restrained to be positive. The reverse holds when access charges are used to subsidize the downstream market. We then analyze the incidence of the imperfect competition on final prices.

This paper argues that the balance of power between producers and retailers depends on the relative degrees of differentiation at the two levels of the vertical structure. We propose an extension of Hotelling’s model in which two producers, competing in prices with horizontally differentiated products, face two horizontally differentiated retailers also competing in prices. We study the setting of producers’ and retailers’ margins. We show that when retailers are more differentiated than producers, they dominate the relationship and their margin is higher than producers’.