Complete Versus Partial Collusion in Competing Coalitions

In this paper, we develop a non-cooperative game theoretic model for our problem context in which the competing producers adopt one of the two alternate production and marketing technologies — efficient and inefficient. We examine stability related implications of the producers' decisions regarding the choices of (i) technologies, (ii) coalition formation, (iii) coalition form, (iv) intensity of collusion. The coalitions can adopt either complete collusion or partial collusion by determining intensity of collusion using endogenously determined sharing rules. The motivation for our study comes from the Costa Rican coffee industry and interesting findings presented in the existing literature focusing on a variety of competing-coalitions settings. Our results can be categorized as: (i) Nash equilibrium of the endogenously determined sharing rules, (ii) the equilibrium coalition forms, and (iii) stability of coalitions. They highlight the dynamics between the number of coalition producers and the cost of inefficiency. We show that the equilibrium sharing rules may have interior solutions and they are not necessarily (a)symmetric. We also show that both coalitions forming complete collusion of the respective producers in not always a Nash equilibrium, and the equilibrium coalition forms need not be (a)symmetric. Our main contribution to existing literature rests in determining the situations in which (i) competing players form coalitions, and (ii) they adopt the coalition form of either complete or partial collusion. Moreover, we provide an alternate explanation to why competing producers horizontally merge in the presence of a competing coalition adopting partial collusion in spite of the merger paradox. We also show that none of the two types of producers considered in this paper have any incentives in not making the information on their coalition form public. Moreover, we establish that situations yielding stable coalitions always exist. Our results demonstrate that the cost advantage to the efficient producers decreases in the number of producers adopting the efficient technology, and the coalition stability related conditions need not imply better profitability for one type of producer vis-à-vis the other. Our model essentially provides a platform for future research in a variety of competing-coalitions settings adopting endogenously determined sharing rules.