Although previous work shows strong relationships between oil prices and economic activity, the empirical evidence on the impact of oil prices on stock market returns has been mixed. This article investigates the existence of long-term relationships between oil prices and stock market indices in Europe using both aggregate and sector indices and linear and asymmetric cointegration. Our findings show that the response of stock prices to oil price depends greatly on the sector of activity and that oil prices affect stock returns in an asymmetric fashion.

Under the Cross-Licensing system (CL), firms are allowed to trade non cooperatively the results of R&D efforts, and compete in the innovation and production stages. First, the paper proposes a simple modeling of this system. Second, a relevant comparison is made with the Cartelized Research Joint Venture (RJV), the form of R&D cooperation recognized to be the best one.

We prove that the Cross-Licensing system may be socially better than the Cartelized RJV. In terms of antitrust policy, for firms, the most favorable collusion mode is Joint Exploitation. We prove that firms are equally tempted by this mode, whether they are under CL or under Cartelized RJV.

Le but de cet article est de montrer que le mécanisme de sélection naturelle des firmes peut entraver la croissance de la productivité agrégée de l'économie, et ce, contrairement aux résultats suggérés par la littérature théorique existante. Cette dernière considère que le mécanisme de sélection des firmes se base sur les niveaux de productivité de celles-ci. Nous supposons, dans cet article, que les firmes sont hétérogènes par non seulement leurs niveaux de productivité mais aussi par leurs coûts fixes. En outre, en tenant compte d'une possible perte d'expérience pour les firmes inactives, notre étude met clairement en avant un effet négatif de la sortie des firmes, et par là d'une baisse des subventions accordées à celles-ci, sur la croissance de la productivité agrégée tant à court qu'à long terme.

This paper studies the production strategies of firms in a duopoly market of homogenous products characterized by quantity competition. Demand is partially unknown and firms are free to produce once, whenever they want before the existence of demand. We show that the nature of the equilibrium in such a game depends on the importance of the information spillovers between a leader and a follower. A Pareto-optimal sequential entry may happen. Therefore, the existence of information spillovers can be sufficient to bypass the leader's rent dissipation result in a duopoly quantity competition framework.