Marsh & McLennan Companies (NYSE: MMC) is a professional services company that provides risk, insurance, and consulting services to clients across a broad range of industries. It makes money through advisory fees, commissions, and service fees generated across two segments: Risk and Insurance Services and Consulting. Risk and Insurance Services, which includes Marsh Risk and Guy Carpenter, produced $17.3B in FY2025 GAAP revenue, while the Consulting segment, comprising Mercer and Marsh Management Consulting, produced the remainder of the company's $27.0B in total FY2025 revenue. Total revenue grew 10% year over year from $24.5B in FY2024. Operating income reached $6.2B in FY2025, up 7% from $5.8B in FY2024. Mercer's three sub-segments, Wealth ($2.8B), Health ($2.3B), and Career ($1.1B), reflect fee-based advisory and brokerage work in human resources and investment consulting. The company is listed on the NYSE under the ticker MMC and competes across all its businesses with intense competition from multiple providers.

Revenue model

Revenue is generated through advisory fees, commissions, and service fees across two segments. Risk and Insurance Services includes Marsh Risk ($14.4B GAAP revenue, FY2025) and Guy Carpenter ($2.5B GAAP revenue, FY2025), plus fiduciary interest income ($403M, FY2025). The Consulting segment includes Mercer ($6.2B GAAP revenue, FY2025) and Marsh Management Consulting. Fiduciary interest income is reported separately within Risk and Insurance Services.

Products and services

Products and services include insurance brokerage and risk advisory (Marsh Risk), reinsurance brokerage (Guy Carpenter), human resources consulting and investment advisory (Mercer, with Wealth, Health, and Career sub-lines), and management consulting (Marsh Management Consulting). Mercer also operates Mercer Trust Company, a limited-purpose New Hampshire chartered trust bank serving U.S. investment management clients. MMA provides benefits insurance consulting and brokerage services.

Customers and end markets

Clients span corporate and institutional buyers of insurance, reinsurance, and professional services. Mercer serves clients with employee benefits, investment management, and human capital needs. The filing does not disclose specific customer concentration data or top-client revenue percentages.

Value-chain role

Marsh & McLennan sits between insurers, reinsurers, and asset managers on one side and corporate or institutional clients on the other, acting as an intermediary, advisor, and broker. It does not underwrite insurance risk; it advises on, places, and manages it on behalf of clients.

Geographic exposure

Revenue is generated globally. Marsh Risk reported FY2025 GAAP revenue of $5.8B from international markets (EMEA: $3.8B, Asia Pacific: $1.5B, Latin America: $571M) and $8.5B from the U.S./Canada. The company is subject to regulatory oversight in the U.S., U.K., E.U., Australia, and other jurisdictions.

Source: SEC 10-K, filed 2026-02-09

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