Abstract. Consumer cooperatives represent a highly successful example of democratic form of enterprises operating in developed countries. They are usually medium to largescale companies competing with the pro…t-maximizing …rms in the retail sector. This paper describes this situation as a mixed oligopoly in which consumer cooperatives maximize the utility of consumer-members and, in return, refund them with a share of the pro…ts corresponding to the ratio of their individual spending to the cooperative's total sales. We show that when consumers possess quasi-linear preferences over a bundle of symmetrically di¤er-entiated goods, and companies operate using a linear technology, the presence of consumer cooperatives positively a¤ects total industry output, as well as welfare. The e¤ect of cooperatives on welfare proves to be even more signi…cant when goods are either complements or highly di¤erentiated, and when competition is à la Cournot rather than à la Bertrand.Keywords: Consumer Cooperatives, Pro…t-maximizing Firms, Mixed Oligopoly.
JEL codes: L13, L21, L22, L31, L33, L81, P13Date: May 2011. Corresponding author: Marco A. Marini, Università degli Studi di Urbino "Carlo Bo" and CREI, Università Roma III. Address: via Sa¢ , 42, 60129, Urbino (Italy). Tel. +39-0722-305557; Fax: +39-0722-305550. E-mail: marco.marini@uniurb.it.Alberto Zevi, Università degli Studi di Roma, La Sapienza, Roma (Italy).E-mail: alberto.zevi@uniroma1.it and zeviecon@libero.it.We wish to thank Gani Aldashev, Panu Kalmi, Michael Kopel, Clemens Lö-er, Domenico Mario Nuti, Jean-Philippe Plateau, two anonymous referees and the participants of the AISSEC Conference in Siena, the IAFEP Conference in Trento, the MDEF Workshop in Urbino, the CREI Seminar in Rome and the FUNDP seminar in Namur for their useful comments and discussions.