While quantitative easing has received much press, qualitative easing has been neglected. Qualitative easing consists of policies that deteriorate the average quality of the assets that a central bank holds. This can occur both with and without quantitative easing.
By selling high quality assets (i.e., foreign exchange, government bonds, or gold) to buy low quality assets (i.e., asset backed securities, or granting loans to a tumbling banking system), there may be qualitative easing without an increase of the central bank´s balance sheet (i.e., without quantitative easing). This was the strategy of the Fed before Lehman Brothers collapsed in September 2008. When the purchase of low quality assets is not sterilised, there is quantitative and qualitative easing at the same time. This has been the strategy of the ECB during the financial crisis and the Fed after Lehman.
Why is the average quality of the assets of a central bank important? There are four main reasons.