Monetary Policy Transmission with Interbank Market Fragmentation

This paper shows how interbank market fragmentation disrupts the transmission of monetary policy. Fragmentation is the fact that banks, depending on their country of location, have different probabilities of default on their interbank borrowings. Once fragmentation is introduced into standard theoretical models of monetary policy implementation, excess liquidity arises endogenously. This leads short‐term interest rates to depart from the central bank policy rates. Using data on monetary policy operations, I show that this mechanism has been at work in the euro area since 2008. The model is used to analyze conventional and unconventional monetary policy measures.