Monopolistic Competition, Multiproduct Firms and Product Diversity

Monopolistic Competition, Multiproduct Firms and Product Diversity

Author: Gianmarco I.P Ottaviano

Publisher:

Published: 2011

Total Pages: 0

ISBN-13:

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This paper has two objectives. First, it presents a linear model of monopolistic competition in which weak strategic interactions among single-product firms are allowed for. Second, it extends this model to the case of multiproduct firms, thus showing how product diversity is affected by strong strategic interactions among oligopolists. In our setting, monopolistic competition with single-product firms is a good approximation of oligopolistic competition with multiproduct firms either when varieties are sufficiently differentiated or when scope economies are low.


Optimal Choice of Product Scope for Multiproduct Firms Under Monopolistic Competition

Optimal Choice of Product Scope for Multiproduct Firms Under Monopolistic Competition

Author: Robert C. Feenstra

Publisher:

Published: 2007

Total Pages: 34

ISBN-13:

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In this paper we develop a monopolistic competition model where firms exercise their market power across multiple products. Even with CES preferences, markups are endogenous. Firms choose their optimal product scope by balancing the net profits from a new variety against the costs of "cannibalizing" their own sales. With identical costs across firms, opening trade leads to fewer firms surviving in each country but more varieties produced by each of those firms. With heterogeneous costs, the number of firms surviving in equilibrium is quite insensitive to the market size. When trade is opened, more firms initially enter, but the larger market size reduces the cannibalization effect and expands the optimal scope of products. As a result, the less efficient firms exit, and the larger market is accommodated by more efficient firms that produce more varieties per firm on average.


On Monopolistic Competition and Optimal Product Diversity

On Monopolistic Competition and Optimal Product Diversity

Author: Pierre M. Picard

Publisher:

Published: 2009

Total Pages: 0

ISBN-13:

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In the Dixit-Stiglitz model of monopolistic competition, entry of firms is socially too small. Other authors have shown that excess entry is also a possibility with other preferences for diversity. We show that workers' rents also contribute to explain excess entry through a general equilibrium mechanism. Larger wages indeed raises the aggregate earnings and firms sales and profits, which entices too many firms to enter. We discuss the possibility of over-provision of varieties by comparing the equilibrium to unconstrained and constrained social optima and to other regulatory frameworks where wages are not controlled. (D'après le modèle de concurrence monopolistique de Dixit et Stiglitz, le nombre de firmes présentes sur un marché est socialement trop faible. Plusieurs auteurs ont utilisé d'autres préférences pour montrer qu'il est aussi possible que la concurrence monopolistique mène à un nombre trop important de firmes. Nous utilisons un mécanisme d'équilibre général pour montrer que la présence d'un nombre excessif de firmes peut aussi être causé par la rente que les travailleurs syndiqués peuvent obtenir. Des salaires élevés accroissent les revenus de l'économie dans son ensemble, ce qui accroît les ventes des firmes et donc leurs profits. De la sorte, trop de firmes risquent d'entrer sur ce marché. Nous comparons l'équilibre décentraliséà un optimum social non contraint, à un optimum social contraint et à d'autres cadres de régulation où les salaires ne sont pas contrôlés.).