AT&T is a holding company. Through its subsidiaries, the company is a provider of telecommunications, media and technology services. The company's Communications segment provides wireless and wireline telecom, video and broadband services. The company's WarnerMedia segment includes media and entertainment businesses that principally develop, produce and distribute feature films, television content, and other content globally; and operate digital media properties. The company's Latin America segment provides entertainment services in Latin America and wireless services in Mexico. The company's XANDR segment relies on using data from its customer relationships, to develop digital and video advertising that is relevant to consumers.

Telefonica is engaged in the provision of public or private telecommunications services, including ancillary or complementary telecommunications services or related services. Co.'s fixed business includes: traditional fixed telecommunication services, Internet and broadband multimedia services, data and business-aplications services, and wholesale services for telecommunication operators. Co. also provides a range of mobile and related services and products to consumer and business customers, including mobile voice services, value added services, mobile data and Internet services, wholesale services, corporate services, roaming, fixed wireless, and, trunking and paging.