Telefónica, S.A. is a Spanish multinational telecommunications company with registered office and headquarters located in two different places, both in Madrid, Spain. It is one of the largest telephone operators and mobile network providers in the world. It provides fixed and mobile telephony, broadband, and subscription television, operating in Europe and the Americas. As well as the Telefónica brand, it also trades as Movistar, O2, and Vivo. The company is a component of the Euro Stoxx 50 stock market index. Wikipedia