Équilibres de sous-emploi, défauts de coordination des activités décentralisées et externalités d'échange

General equilibrium models of coordination failures capture the rationale of decentralised private activities. Nevertheless, the modelling of decentralized transactions and their influence at the macro-level are often eluded. In this paper, we explore a search theoretic monetary model without auctioneer and with trade-frictions, in which macro-underemployment is caused by a lack of coordination in decentralized trades. The equilibrium concept is a steady state with self-fulfilling expectations concerning the trade sector. There are multiple Pareto-ranked inefficient equilibria. Externalities arise from the transaction technology and money plays a critical role in coordinating transactions. We show that the acceptability of money yields a Pareto improvement because its use in trade makes production decisions easier. Moreover, when the degree of specialisation in consumption is low, more money enhances welfare and increases production. We finally discuss the model through the literature.