Growth in wireless communications is taking American Tower to new heights. The tower management company operates more than 40,400 broadcast and wireless communications towers and distributed antenna systems in the US, and nearly 60,200 more in emerging markets in Asia and Central and South America. It rents space on towers and rooftop antenna systems to wireless carriers and radio and TV broadcasters, who use the infrastructure to enable their services. American Tower also offers some tower-related services: construction site acquisition, structural analyses to determine support for additional equipment, and zoning and permitting management services. Its top tenants include AT&T, Sprint Nextel, and Verizon.