The effects of the purchases are transmitted through various channels: they have a direct impact on the yields of 5  the securities being purchased; they help to improve credit supply conditions; and they strengthen the monetary stimulus to the entire economy through wealth and portfolio-rebalancing effects.
The consequences of a reduction in the key interest rates to even more negative levels – the true ‘non-standard’ instrument among those that have been introduced thus far, given that open market operations have always been in the toolbox of central banks – should be assessed more carefully.