Top 10 US Insurance Brokers and Agents by Revenue

Insurance brokers earn primarily through commissions and fees on the premium they place, not by underwriting risk themselves — which means the revenue figures on this list measure something closer to deal flow and client relationships than balance-sheet scale. A broker can place enormous premium volume for clients while reporting comparatively modest revenue, because commission rates vary by line of business and negotiated fee arrangements.

That distinction is why this list looks different from a ranking of insurers by premium written: Marsh McLennan and Aon lead here because they broker and advise at scale across the largest corporate accounts globally, not because they carry underwriting risk the way an insurance carrier does.

Nearly every name on this list has grown substantially through acquisition rather than organic expansion — Arthur J. Gallagher's acquisition pace, Aon's purchase of NFP, and the broader trend of private-equity-backed roll-ups like Hub International and BRP Group buying up independent regional agencies are all the same underlying pattern.

The blocked 2021 merger between Aon and Willis Towers Watson is the clearest sign of where this consolidation hit a regulatory ceiling: antitrust concerns stopped the two largest players from combining, but did nothing to slow the smaller, less scrutinized roll-ups happening throughout the rest of the list. Lockton's position as the largest broker that has deliberately stayed private and independent is the closest thing to a counter-trend here.