Marsh McLennan Agency | 171,723 followers on LinkedIn. Marsh McLennan Agency (MMA) provides business insurance, employee health & benefits, retirement & wealth, and private client insurance solutions to organizations and individuals seeking limitless possibilities. With over 15,000+ colleagues and 300+ offices across the United States and Canada, MMA combines the personalized service model of a local consultant with the global resources and expertise of the world’s leading professional services firm, Marsh McLennan (NYSE: MMC). MMA generates more than $5 billion in annualized revenue, making it one of the largest brokerage operations in North America.