Marsh & McLennan Companies, Inc. (MMC) Stock Analysis

Marsh McLennan’s competitive edge rests on four primary pillars: global scale, service breadth, client relationships, and innovation.¹²

First, MMC is the world’s largest insurance broker, with $24.5 billion in 2024 revenue³ and operations in over 130 countries⁴. This scale enables superior data access, risk insights, and negotiating leverage with insurers—advantages that smaller rivals such as Arthur J. Gallagher or Lockton cannot match. Aon and Willis Towers Watson are the only true global peers, but MMC’s broader consulting footprint (via Mercer and Oliver Wyman) provides additional cross-selling opportunities and client stickiness⁵.

Second, MMC’s diversified business model—spanning risk and insurance services, reinsurance, health, wealth, and management consulting—reduces reliance on any single market or product. In 2024, Risk & Insurance Services contributed 63% of revenue, with Consulting at 37%.⁶ This mix provides resilience through economic and insurance cycles.

Third, MMC’s client retention rates are among the highest in the industry, supported by long-standing relationships with large corporates and public entities. Its reputation for expertise and reliability is a barrier to client churn.⁷⁸

Finally, MMC invests heavily in technology and analytics, exemplified by proprietary platforms like Sentrisk and Blue[i].⁹ These tools enhance risk modeling and client value, helping to defend margins as digital disruption intensifies.¹⁰

In sum, MMC’s scale, breadth, and innovation underpin a durable competitive advantage over both global and regional rivals.¹¹¹²