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.

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.