Teléfonos de México, S.A.B. de C.V., known as Telmex is a Mexican telecommunications company headquartered in Mexico City that provides telecommunications products and services in Mexico. In 2014, Telmex was the dominant fixed-line phone carrier in Mexico. In addition to traditional fixed-line telephone service, Telmex offers Internet access through their Infinitum brand of Wi-Fi networks, data, hosted services and IT services. Telmex owns 90 percent of the telephone lines in Mexico City and 80 percent of the lines in the country. Telmex is a wholly owned subsidiary of América Móvil.

América Móvil, S.A.B. de C.V. is a Mexican telecommunications corporation headquartered in Mexico City, Mexico. It is the 7th largest mobile network operator in the world in terms of equity subscribers, as well as one of the largest corporations in the world. América Móvil is a Forbes Global 2000 company. As of Q1, 2019, América Móvil had 277.4 million wireless subscribers, and 84.3 million fixed revenue generating units.