Introduction

Abstract

En
The purpose of this article is to show that there is a gap in the literature on the sources of monopoly power. It looks at the literature on the history of different topics (Industrial Organization, Models of profit maximization in non-competitive markets, Antitrust, Competition) to find out which kind of limitation to entry economists before Bain took into account, the role they attributed to the number of firms present in the market, and their ideas on potential competition. It finds that there are good reasons to investigate the sources of market power in the Italian marginalist thought. The paper demonstrate that: 1. new filiations of ideas can be traced; 2. entry is not considered before 1950s only in analytical models, while in non formalized theory there is a lot on this notion; 3. economists were perfectly aware of the situation between perfect competition and monopoly before 1930s; 4. Italian marginalists used a kind of theory of strategic competition, which was an adaptation of the classical theory of competition; 5. competition policies were requested in 19th century not only in the U.S.