Crucial to success, Commerzbank says, is knowing why you are merging.
For some companies it is clear. Former monopolist Deutsche Telekom, for example, has seen its domestic market share drop to 70% after the telecom markets were liberalised. Ever since, chief executive Ron Sommer has been looking for overseas partners to help recoup the losses.
Cut and thrust
It seems a ruthless approach is the key. When UK bank Lloyds bought Cheltenham & Gloucester and then TSB, it was not afraid to wield the cost-cutting scalpel.
But the shareholder 'value' delivered by sacking workers and closing branches has to be offset against the price of the acquisition to assess how much money has really been made.
Mergers born out of defensive intentions are generally deemed unlikely to fare well.
Stephen Barrett, head of mergers & acquisitions at accountants KPMG, said: "When they don't work, the two key management groups do not blend well together.
"The important thing in a merger is to make it crystal clear who is going to lead the operation."
