Marsh is a global professional services firm, headquartered in New York City with operations in insurance broking and risk management.

[3] Marsh's insurance brokering and risk management business began in the first decade of the twentieth century, when it was formed by Henry Marsh and Donald McLennan with operations in New York City and Chicago, where McLennan had studied railroad risk and insurance needs by spending 30 days riding the rails.

In early 2005, Marsh agreed to pay $850 million to settle the lawsuit and compensate clients whose commercial insurance it arranged from 2001 to 2004.

But, by Q3 2006, brokerage revenue had stopped declining, and the company's profits again began to grow, thanks in part to a cost-cutting regime.

[7] In July 2017, Marsh expanded Doyle's role, naming him President and CEO after Zaffino's departure to AIG.