It was a rare good day to be a Greek bank. Suggestions that the European Central Bank may extend its government bond purchasing programme gave hope to lenders sitting on stores of shunned “peripheral” euro-zone bonds. But even after today’s boost, Greek bank shares closed at around half of their value at the start of the year. Recently published financial results from the country’s largest lenders showed steadily rising provisions against sour loans, with little sign of a let-up any time soon.