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.

BT is a communications services company, delivering products and services with industry-specific communications solutions and consulting expertise. Co.'s principal activities include: networked IT services; local, national and international telecommunications services; broadband and internet products and services; and converged fixed/mobile products and services. Co. operates five lines of businesses: BT Global Services, BT Business, BT Consumer, BT Wholesale and Openreach, providing services to around 6,500 large corporate and public sector customers, in more than 170 countries worldwide.

Calix is a provider of cloud and software platforms, systems and software for fiber- and copper-based network architectures. The company is also a provider of software defined access and cloud products focused on access networks and the subscriber. The company's portfolio allows for a range of subscriber services to be provisioned and delivered over a single unified network. The company's access systems can deliver voice and data services, broadband services, mobile broadband, as well as high-definition video and online gaming. The company's premises systems enable communications service providers to manage the smart home and business and provide new services to their device enabled subscribers.

T-Mobile US provides mobile communications services, including voice, messaging and data, under its brands, T-Mobile and Metro? by T-Mobile, in the United States, Puerto Rico and the United States Virgin Islands. The company provides mobile communications services using its 4G Long-Term Evolution network and its 5G technology network. The company also provides various wireless devices, including handsets, tablets and other mobile communication devices, and accessories for sale, as well as financing through Equipment Installment Plans and leasing through JUMP! On Demand?. The company provides reinsurance for handset insurance policies and extended warranty contracts offered to its mobile communications customers.

Verizon Communications is a holding company. Through its subsidiaries, the company provides communications, information and entertainment products and services to consumers, businesses and governmental agencies. The company has two reportable segments, Verizon Consumer Group (Consumer) and Verizon Business Group (Business). The company's Consumer segment provides consumer-focused wireless and wireline communications services and products under the Verizon brand and through wholesale and other arrangements. The company's Business segment provides, among others, wireless and wireline communications services and products, video and data services, corporate networking solutions, security and managed network services.