debitel AG is one of the largest mobile telephone services providers in Europe, offering a wide range of telecommunication products – mobile and land-line telephony as well internet services. At its peak, the business commanded a 47% market share of the mobile service provider market in Germany (its largest market) with 12.4% of the overall mobile telephone market as of 2004[update]. The company boasted over 10.2 million customers of which 8.3 million were resident in Germany.
The company was founded in 1991 by debis, a subsidiary of German car maker Daimler Benz before being sold in 2004 to a German holding company of Swiss telecommunications giant Swisscom.
In June 2004, Permira, an international private equity firm, acquired Swisscom's 95% stake in debitel.
In 2006 it was announced that debitel would merge with _dug telecom AG, a German telecommunications company with 430 outlets of its own which had been founded in 1993 as a mobile telephone direct sales company called ‘Dittrich und Grella’.
Including the 1100 employees of _dug, by March 2008 the merged company employed 4000 people. In October 2008 the company owned 500 outlets in Germany, marketing what are known in Germany as 'tariff-based' products under the debitel brand on behalf of network providers such as T-Mobile, E-Plus und O2. debitel also sold land-line services at this time for Deutsche Telekom's T-Home brand, Arcor, O2 DSL, Alice (a German brand owned by Telecom Italia) and Freenet.
In July 2007 debitel was granted permission by the EU Commission to take over Elmshorn-based telecommunications company Talkline.