As part of its efforts to revitalise the euro zone economy, the ECB has already cut interest rates to the lowest they have ever been, but this has not been met with the expected boost to borrowing, or growth. There are now worrying signs of a slide back into recession for the euro zone as even stalwart Germany falters.
On of of this, the ECB risks the "liquidity trap"; a situation described by economist John Maynard Keynes whereby injections of cash into private banks are having no effect on interest rates or monetary policy.
The next step for ECB President Mario Draghi could be the launch of a bond-buying – or quantitative easing – program. However, the process is riddled with problems for the ECB: there are no common euro zone bonds so the bank would have to pick one country over another, plus there is nothing in the bank's founding charter that allows for such an action.