O2 (UK) O2 (UK) Telefónica UK Limited (trading as O2 – stylised as O) is a telecommunications services provider in the United Kingdom, owned by the Spanish multinational Telefónica, and is headquartered in Slough. With 25 million subscribers (as of December 2017), O2 is the second-largest mobile network operator in the United Kingdom after EE, with Vodafone in third place. O2 was formed in 1985 as Cellnet, a 60:40 joint venture between BT Group and Securicor. In 1999, BT Group acquired Securicor's share of Cellnet and the company was later rebranded as BT Cellnet. In June 2000, BT Cellnet launched the world's
Monopoly Nassau and Suffolk counties of New York, and the Rockaway Peninsula in Queens. The Comcast Corporation is the largest mass media and communications company in the world by revenue. It is the largest cable company and home Internet service provider in the United States, and the nation's third largest home telephone service provider. Comcast has a monopoly in Boston, Philadelphia, and many other small towns across the US. The United Aircraft and Transport Corporation was an aircraft manufacturer holding company that was forced to divest itself of airlines in 1934. Iarnród Éireann, the Irish Railway authority, is a current monopoly