O2 (UK) they can do it too" in reference to Vodafone and EE, O2's biggest competitors and the UK's top three mobile-telecoms companies. 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
SBA Communications SBA Communications SBA Communications Corporation owns and operates wireless infrastructure, including small cells, indoor/outdoor distributed antenna systems, and traditional cell sites that support antennas used for wireless communication by mobile carriers and wireless broadband providers in the United States and its territories, as well as in Canada, Central America, and South America. The company operates in two segments, Site Leasing and Site Development. SBA Communications Corporation leases antenna space to wireless service providers on towers that it owns or operates; and manages rooftop and tower sites for property owners under various contractual arrangements. As of December 31, 2013, it owned