ADP vs AMT Comparison

Automatic Data Processing, or ADP, is a global, cloud-based human capital management provider offering payroll, compliance, talent management, benefits administration, and retirement services. The firm also provides HR outsourcing services, including PEO offerings, enabling clients to reduce HR overhead. Its broad suite serves customers of all sizes across diverse sectors, and the firm holds large market shares in its core markets. As of fiscal 2025, ADP counts over 1.1 million clients and manages payroll for more than 42 million workers across 140 countries.

American Tower owns and operates about 150,000 wireless towers throughout the US, Asia, Latin America, Europe, and Africa. It also owns and/or operates 30 data centers in 11 US markets through its CoreSite segment. The company's customer base in the tower business is very concentrated, with most revenue in each market generated by the top three or four mobile carriers. The company operates 42,000 towers in the US, which accounted for about half of total revenue in 2025. Outside the US, American Tower operates about 47,000 towers in Latin America (dominated by Brazil), 33,000 towers in Europe, and 28,000 towers in Africa. American Tower operates as a REIT.