Some large Greek banks may have to be shut and taken over by stronger rivals as part of a restructuring of the sector that would follow any bailout of the country, European officials have told Reuters. One official said that Greece’s four big banks – National Bank of Greece (NBGr.AT), Eurobank (EURBr.AT), Piraeus (BOPr.AT) and Alpha Bank (ACBr.AT) – could be reduced to just two, a measure that would doubtless encounter fierce resistance in Athens.