Marsh & McLennan Companies, Inc., doing business as Marsh McLennan and Marsh, is a global professional services firm, headquartered in New York City with businesses in insurance brokerage, risk management, reinsurance services, talent management, investment advisory, and management consulting. Its four main operating companies are Marsh (53% of 2024 revenues), which offers risk management, insurance broking, insurance program management, risk consulting, analytical modeling and alternative risk financing services; Marsh Re (formerly Guy Carpenter; 10% of 2024 revenues), a reinsurance intermediary and advisor; Mercer (23% of 2024 revenues), which provides consulting to employers for health insurance, retirement plans, and pension plans; and Oliver Wyman; 14% of 2024 revenues, including Lippincott and NERA Economic Consulting, which provides consulting services. In 2024, Risk and Insurance Services contributed a total of 63% of revenues and 71% of operating profit, while Consulting contributed 37% of revenues and 29% of operating profit.
It is the largest insurance broker worldwide.
