This paper develops a theoretical model of financial intermediation with three original features: first, consideration of all sectors within total outstanding credits, including households; second, the possibility of a non monotic relationship between prices and funding supply volumes in periods of high financial strains; last, the link between interbank credit rationing and other sectors funding rationing. The central bank conducts an unconventional type monetary policy. We show that the intermediation chain characteristics then determine the conditions of transmission of a shock on financing costs and the modalities for the resulting monetary policy.