SUMMARY
Oligopoly and oligopsony have been studied extensively. However, the dual figure of the oligopsonistic-oligopolistic intermediary has not been. This dual personality has a double negative impact on the market, on one hand reduces the demand to producers who face a competitive market, lowering prices as buyers, and on the other hand reducing its offer by raising the prices as sellers. In this way, their benefits are increased buying cheap and selling expensive, affecting effective demand of the consumer and the effective supply of the initial producer.