The actual impact of purchase operations on yields has been found to be less in comparison.2 The issue is rather if it matters how a given stock of purchases is built up, and how this building up interacts over time with the other elements of the monetary policy stance.
This is especially important for the ECB today because, as we said in our latest introductory statements, our monetary support currently comprises three components: first, net asset purchases; second, the stock of acquired assets and forthcoming reinvestments; and third, our forward guidance on interest rates.