Equal rights to trade and mediate

For economies with a fixed finite set of traders, few results characterize Walrasian equilibria by their social choice properties. Pareto efficient allocations typically require lump-sum transfers. Other characterizations based on the core or strategyproofness apply only when, as in continuum economies, agents cannot influence prices strategically. Or the results concern social choice with a variable number of agents. This paper considers allocations granting agents equal rights to choose net trade vectors within a convex cone and, in order to exclude autarky, an additional right to mediate mutually beneficial transactions. Under standard assumptions, these properties characterize Walrasian equilibria without transfers. JEL Classification: D63, D50.