How can a widening of peripheral euro-zone countries’ yield spreads be prevented when the ECB stops its bond purchase programmes?

The peripheral euro-zone countries’ yield spreads are now very low, but this is largely due to the ECB’s expansionary monetary policy. This is because the ECB is buying their bonds, but also because the core euro-zone countries’ yields are so low that investors are switching to peripheral countries’ bonds. But the peripheral countries’ structural characteristics (productivity, employment rate, potential growth, corporate innovation and modernisation, public finances, weight of industry) remain very negative. How then will it be possible to prevent a marked widening of these countries’ yield spreads and another euro-zone crisis once the ECB stops its government bond purchases? There are three possibilities: The ECB does not stop its purchases, but this is hard to believe given the costs involved; Fiscal solidarity, particularly in terms of investment, becomes very strong between euro-zone countries; The ECB, once it stops its purchases, makes it clear that it is prepared to resume them at any time if spreads widen, which would discourage speculation and create an insurance.