KDDI is a telecommunications company. Along with its affiliates, Co. operates in four principal business segments: personal, value, business, and global. Co. is engaged in the sale of mobile handset; and the provision of mobile telecommunication services under "au" brand name, Internet contents, settlement service, and electronic money service for individual customers. Co. offers information and communication technology ("ICT") solution services and data center services for domestic corporate customers, overseas companies and individual customers. Co. is also involved in the call center business, the research and technological development, and the telecommunication facilities maintenance.

NTT DOCOMO is a mobile telecommunications carrier. Co. has three operating segments. The telecommunications segment includes mobile phone services (LTE(Xi) services and FOMA services), optical-fiber broadband service, satellite mobile communications services, international services and the equipment sales related to these services. The smart life segment includes video and music distribution, electronic books and other services offered through DOCOMO's "dmarket" portal, as well as finance/payment services, shopping services and various other services. The others segment primarily includes "Mobile Device Protection Service," as well as development, sales and maintenance of IT systems.