In a general equilibrium model, we allow for households with several, typically heterogeneous, members; households that make (efficient) collective consumption decisions where different households may use different collective decision mechanisms; yet households that operate within a competitive market environment. The interaction of two allocation mechanisms, collective decisions and competitive markets, is investigated, with a focus on the efficiency properties and decentralization possibilities of the dual allocation mechanism.

On the international scene, away from national legal rules, the use of different currencies is largely due to the operation of the “Invisible Hand” The paper develops a three-country model of the world economy. This links real trade patterns with currency exchange structures in a general equilibrium framework which includes transaction costs on foreign exchange markets. In the presence of strategic complementarities, there are multiple equilibrium structures of currency exchange for a given underlying real trade pattern. The existence conditions of these different equilibria are characterized, using the trade links between countries as the key parameters. Finally, repercussions on world output of the choice of a currency exchange structure are analysed.

We investigate the effects of contract renegotiation in multi-agent situations where risk averse agents negotiate a contract offer to the principal after the agents observe a common, unverifiable perfect signal about their actions. We show that renegotiation with multiple agents reduces the cost of implementing any implementable action profile down to the first-best level, even though the principal cannot observe the agents’ actions. Moreover, it is sufficient for the principal to use a “simple” initial contract, in the sense that it consists of no more than a single sharing scheme for each agent and the total payments to the agents are the same regardless of the realised state. An important implication is that decentralization, in the sense of delegated negotiation and proposals from the agents, can be as effective as centralized schemes that utilize revelation mechanisms in unrestricted ways.