Intermédiation et segmentation des marchés

We present a model in which intermediaries that compete with a search market emerge. Agents are heterogenous vis à vis a production cost. They are allowed to choose both their economic activity, becoming a producer or a middleman, and their transaction strategies. Entering the intermediation activity is costly but subject to a free entry condition. The rationale for the existence of middlemen is neither the speeding up of transaction, nor the expertise of the quality of goods. By creating a market place distinct from the search market, they allow producers to direct their search. The equilibrium market structure depends on the operating cost of intermediation. If this cost is too high, intermediation is not a viable activity. If it is low enough, middlemen exist that attract all remaining producers. For intermediate values, both direct and intermediated exchange occur. Welfare analysis shows that the main effect of intermediation is to improve the situation of both high cost and low cost agents ? middlemen and some of their clients ? at the expense of intermediate cost agents. Classification JEL : D40, D51