Marsh McLennan Companies

Head office location: New York, USA 
Market cap: $81.07 billion 
Business lines: Insurance broking and risk management 

Marsh McLennan Companies (MMC) is a professional services firm that’s behind some of the largest insurance companies in the world, including: 

• Marsh: An insurance brokerage and risk management giant, with offices all over the world. Marsh has been credited with advising around 95% of Fortune 1000 companies. 
• Guy Carpenter: Offers reinsurance broking expertise, while also offering strategic advisory services and analytics to consumers.  

MMC is also the parent company of major consulting players Oliver Wyman – a global management consulting firm – and Mercer – a human resources consulting company. 

The table below shows the rest of the 20 largest insurance companies in the world by market cap.