Chief Executive Officer Olaf Koch likes to joke about his surname when discussing plans to split German retail giant Metro Group into two separate entities by mid-2017. Koch means 'cook' in German, so the pleasantry is moderately witty in his home country, however fatal it would be in English-speaking business circles. So, all things considered, perhaps 'magician' would be the better word to use.After all, a man who can make nearly €580m in goodwill disappear off a corporate balance sheet in a perfectly legal way is little less than a financial wizard.