However, these articles do not prohibit the ECB from operating in financial markets by buying or selling marketable instruments, including government debt.14 That is of course natural. In pursuing their statutory objectives central banks operate in a range of financial markets, particularly in government debt markets, since these are large and liquid and since government debt has historically been seen as risk free.
Such operations of course also augment the demand for public debt, thereby reducing the interest rate on the debt and making it easier for governments to finance themselves. But this effect is entirely incidental to monetary policy. 5. Reducing public debts  Public debts are currently very large in many countries and must be reduced.