Drillisch is a holding company. Co. through its subsidiaries, is a mobile virtual network operator in Germany. The services acquired from the network operators Telekom Deutschland GmbH, Vodafone D2 GmbH, E-Plus Mobilfunk GmbH and Telefonica O2 Germany GmbH & Co. OHG are sold further to the end consumers for Co.'s own account and at rates established by Co. Co. organizes its operations into three segments: telecommunications, which includes its activities in the sector of wireless services; freenet holding, which comprises the operations of its freenet AG subsidiary; and software services, which involves activities related to the development and marketing of a workflow management software.

Deutsche Telekom is engaged in the telecommunications services and information technology sectors. Co. operates as an integrated telecommunications provider. It is organized into four operating segments: Germany, Europe, and the United States; and Systems Solutions, as well as Group Headquarters and Shared Services. Co. provides fixed-network lines, broadband lines and mobile communications. Co. also provides customized Information and Communication Technology (ICT) solutions for corporate customers under the T-Systems brand. The Group Headquarters and Shared Services segment comprises cross-segment management functions, real estate services, and mobility solutions, among others.

Telefonica Deutschland Holding is a telecommunication company. Co. offers its consumer retail and business customers postpaid and prepaid wireless communications products, along with wireless data services using Global Packet Radio Service, Universal Mobile Telecommunications System and Long Term Evolution technology as well as Digital Subscriber Line wireline telephony and high-speed internet services. Co. markets its products and its wireless and wireline communications products as well as services via the core brand O2. Co.'s secondary brands include the brands Fonic and netzclub. Co. also markets high-speed DSL internet access and wireline telephony.