3U Holding AG engages in the telephony, renewable energy and services sectors. It operates through the following segments: Telephony, Renewable Energies, Services and Holding/Consolidation. The Telephony segment comprises of the products call-by-call, pre-selection, added-value services, and termination services. The Renewable Energies segment consists of the development, production, trading, and operation of components from the renewable energies area as well as heating and cooling technology. The Services segment comprises of information technology services, systems development, marketing, and consulting. The Holding/Consolidation segment includes operations connected with the construction of the solar power plant. The company was founded by Udo Graul, Manfred Schwarz, Michael Schmidt, and Roland Thieme on August 26, 1997 and is headquartered in Marburg, Germany.