1. 1 Competition Among the Big and the Small Ken-Ichi Shimomura and Jacques-François Thisse

2. 2 Armchair evidence shows that many industries are characterized by the coexistence of a few large commercial or manufacturing firms, which are able to affect the market outcome, as well as of a myriad of small family-run businesses with very few employees, each of which has a negligible impact on the market To the best of our knowledge, such a mixed market structure has been overlooked in the literature

3. 3 According to Schumpeter “In the case of retail trade the competition that matters arises not from additional shops of the same type, but from the department store, the chain store, the mail-order house and the supermarket which are bound to destroy those pyramids sooner or later”

4. 4 Bertrand and Kramarz (2002) have showed that the Royer-Raffarin Law that the enforcement of this law has had a negative impact on job creation.

5. 5 The purpose of this paper is precisely to provide a unified approach to study (i) how those two types of firms interact to shape the market outcome and (ii) whether or not it is socially desirable to have large and/or small firms in business

6. 6 the oligopoly à la Cournot with differentiated products and the monopolistic competition model of the Chamberlin-type Two standard models of industrial organization

7. 7 The mixed market structure model obeys different rules than standard oligopoly models A specific model CES discrete (atoms) and negligible varieties of the differentiated product

8. 8 The Model Two goods Two production sectors One production factor (labor) The first good is homogenous and produced under constant returns and perfect competition The other good is a horizontally differentiated product. It is supplied both by oligopolistic firms and by monopolistically competitive firms (MC-firms)

9. 9 Two sub-sectors governed by different forms of competition Let N > 1 be the number of oligopolistic firms and M > 0 the mass of MC-firms

10. 10 (i) A representative consumer Maximize subject to Price index of the MC-subsector

11. 11 Price index of the differentiated product Demand functions

12. 12 (ii) Oligopolistic firms (iii) MC-firms and

13. 13 The Market Outcome A mixed market equilibrium is defined as a state in which the following conditions simultaneously hold (i) the representative consumer maximizes her utility subject to the budget constraint (ii) both oligopolistic and MC-firms maximize their own profits with respect to output (iii) the mass of MC-firms is positive and they earn zero profits while oligopolistic firms earn positive profits

14. 14 Firms are “income-takers” A symmetric mixed market equilibrium in which all oligopolistic firms choose the same output Q, whereas all MC-firms have the same production policy q Equilibrium price indices

15. 15 Proposition 1. The price at which oligopolistic firms sell their output decreases when the mass of MC-firms increases Proposition 2. There exists a unique symmetric market equilibrium. This equilibrium is mixed if and only if …

16. 16

17. 17 The Industry Structure Proposition 3. Both the equilibrium mass of MC- firms and quantity index of this sub-sector decrease when the number of oligopolistic firms increases

18. 18

19. 19 Proposition 5. The industry price index decreases when the number of oligopolistic firms increases The shrinking of the MC-sector generated by the entry of a large firm is sufficiently strong to permit the expansion of the output of each oligopolistic firm Proposition 4. The equilibrium output of an oligopolistic firm increases when the number of oligopolistic firms rises

20. 20 Is Schumpeter right? The MC-subsector disappears when the number of oligopolistic firms is sufficiently large

21. 21 Welfare Proposition 6. Consider a symmetric mixed market equilibrium, then, the total net income increases when the number of oligopolistic firms increases Proposition 7. Consider a symmetric mixed market equilibrium, then the social welfare increases when the number of oligopolistic firms increases

22. 22 CONCLUSIONS (i) A mixed market with several large firms and a small number of small firms is more efficient than a market with fewer large firms and a larger number of small firms

23. 23 (ii) Considering a traditional economy populated with small businesses, more affluent societies and technological progress have combined to facilitate the entry of a growing number of big firms. This in turn triggers the decline of small businesses in mixed markets endowed with old and small firms as well as modern and big firms. This concurs with the prediction made by many observers, ranging from Karl Marx to Robert Lucas. However, the fall in small firms' fixed costs sparked by the development of the new information technologies has permitted the revival of SMEs.

24. 24 THE BOTTOM LINE THE BOTTOM LINE Small need not be beautiful