عنوان مقاله [English]
The policy interest rate was the main instrument of monetary policy of major central banks during the period of the World War II to the early 2000s. In the 2000s and with the onset of the financial crisis, the policy interest rate fell to zero lower bound and conventional monetary policy instrument was not relevant. Hence, major central banks used unconventional instruments of monetary policy through quantitative easing and credit facilities, endogenous facilities, intervention in the foreign exchange market and changing bank reserves. Channels of the transmission of monetary policy were through signaling and portfolio balance. The post-crisis period and with the normalization of economic conditions, the major central banks planned to return to conventional monetary policy.