The global insurance brokerage industry is dominated by a small group of massive multinational enterprises that lead by annual gross revenue. The top-tier global brokers include Marsh & McLennan as the undisputed industry leader, followed closely by Aon plc, Arthur J. Gallagher & Co., and Willis Towers Watson. These corporate giants command significant global market share by providing comprehensive commercial risk management, employee benefits consulting, and complex reinsurance brokerage services.