Commerzbank shares jumped on market open on Wednesday, after Italian bank UniCredit acquired a 4.5% stake in the Frankfurt-based lender from the German government. Commerzbank stock was up 17.5% at 9:37 a.m. London time. The stake acquisition marks the first step in Berlin's exit from its position in the German lender. The German government said it had sold around 53.1 million shares — or a roughly 4.49% tranche out of its 16.49% total shareholding — in Commerzbank for roughly 702 million euros ($775 millio ...