Résumé
1 er mars 2004 Résumé I show that the presence of informed buyers is necessary but not always sucient for producers to use prices as signals of product quality. A suciently high fraction of informed buyers eliminates the lemons problem. A small fraction of informed buyers mitigates the lemons problem, provided that buyers' prior belief of high quality is suciently pessimistic : price reveals high quality at a signaling cost which increases with market power. However, if buyers' prior belief of high quality is optimistic when the market is poorly informed, then the lemons problem is not overcome.