The Stable Coexistence of Oligopolies and the Competitive Fringe

In this paper, we introduce a simple new theory on mixed competition between oligopolistic firms and the competitive fringe, assuming a comparative advantage for big firms and free entry for small _rms. Oligopolies are defined as conglomerates, each part of which benefits from joint operations through lower costs. Our theory implies that (i) industries with a few oligopolies arise as a stable outcome of mixed competition; (ii) mixed competition differs from the monopolistic competition of single-product firms due to the underproduction of oligopolistic firms and differs from pure oligopolistic competition sine constraints on this underproduction are imposed by the competitive fringe; (iii) a positive shock in the market size an strengthen or weaken the competitiveness of the economy through the growth of the number of oligopolies