Deutsche Bank shares closed down 1.23% on Friday to 12.05 euros, valuing the bank at 25 billion euros ($27.37 billion). Commerzbank shares ended the day little changed at 11.35 euros, valuing it at 14 billion euros. A combination would be complicated by Deutsche Bank's low valuation, assets that would need to be marked down and could lead to painful job cuts to reap the benefits of combining overlapping businesses. It trades at a fraction of its book value.