Bank shareholders have had a tough time. Squeezed margins and weighty regulation have dampened profit and potential for traditional banks around the globe. In contrast to buoyant stock-markets more generally, the absolute and relative decline in their share prices has followed inexorably. Some argue that bank shares are now ‘cheap’ and represent an attractive investment opportunity. In many cases trading below the balance sheet valuation of their equity, they argue that even a modest improvement in business performance would spark a sharp rebound in bank share prices. They may well be right. But before committing hard-earned savings in the hope…