In an interview with the Financial Times, Miguel Fernández Ordóñez, governor of the Bank of Spain, outlined plans for a series of mergers within months among the “cajas de ahorros”, regional savings and loans institutions.

“I think there are at least 15 institutions that should merge with others,” he said. “I hope  next spring we have restructured all these institutions, that’s my idea. We now have many, many mergers that we are discussing.”

Spain’s listed commercial banks, some of which were involved in previous domestic banking crises, have so far survived the global financial crisis in better shape than many of their international rivals.

But the unlisted “cajas” , many of them politicised, linked to regional governments and with an opaque ownership structure ,seized market share from the banks at the peak of the recent housing boom and now account for about half of outstanding loans in Spain. Several are heavily exposed to bankrupt property developers and homeowners unable to meet mortgage payments.