The art of central banking of the ECB and the separation principle

This paper examines the art of central banking as practised by the European Central Bank (ECB) through the prism of Goodfriend's (2009) determination of the three policies that fall within the remit of a central bank: monetary policy, which consists in varying the size of the balance sheet, credit policy, which consists in modifying the credit structure, and interest rate policy, which consists in adjusting the interest rates of the marginal lending and deposit facilities. The theoretical literature emphasises the existence of a separation principle between the first policy, which seeks to ensure monetary stability and the other two policies, which are intended to ensure financial stability through the smooth functioning of the interbank money market. This paper shows in particular that a central bank not only has the capacity but indeed must strive to separate the conduct of its monetary policy, which must seek to ensure medium and long-term price stability, from that of its credit policy, which is driven by short-term imperatives and consists in supplying the banking system with liquidity in the event of temporary money demand shocks. During the first part of the crisis, the ECB acted in accordance with the separation principle. However, it became increasingly difficult to apply as interest rates approached the zero-lower-bound. In effect, the unconventional measures adopted by the ECB created interference between its monetary policy, its credit policy and its interest rate policy.