MMC vs ADP Comparison

Marsh McLennan is a professional services firm that provides advice and solutions in the areas of risk, strategy, and human capital. The company operates through two main segments: risk and insurance services and consulting. In risk and insurance services, the firm offers services via Marsh (an insurance broker) and Guy Carpenter (a risk and reinsurance specialist). The consulting division comprises Mercer (a provider of human resource services) and Oliver Wyman (a management and economic consultancy). About half of its revenue is generated outside the US.

Automatic Data Processing is a global technology company providing cloud-based human capital management solutions, enabling clients to better implement payroll, talent, time, tax, and benefits administration. Additionally, ADP provides human resource outsourcing solutions that permit customers to offload some of their traditional HR tasks. The company operates through two segments: employer services and professional employer organization services. Employer services consist of the company's HCM products as well as a la carte HRO solutions. PEO services contain ADP's comprehensive HRO solution, where it acts as a co-employer with its customer. As of fiscal 2025, ADP serves over 1.1 million clients and pays over 42 million workers across 140 countries.