Obermann, 49, has been with Deutsche Telekom for 16 years. By late 2006, he had risen to become the youngest ever CEO of a German blue-chip, at just 43.
When he took over, Deutsche Telekom was a lumbering giant with customers leaving in droves and investors wary of its ability to deliver. As chief executive his image has been of a low-key and somewhat uninspiring leader, eager to keep unions and politicians happy and wary of taking big strategic decisions.
He suffered a blow last year when a deal to sell Deutsche Telekom's troubled T-Mobile USA business, which has been losing market share, to AT&T collapsed.
This month, Deutsche Telekom cut dividends for the next two years by almost a third investments at home and in the United States eat away cash.