Top 10 US Insurance Brokers and Agents by Revenue

$16B in revenue, 30% less than Marsh McLennan. London-headquartered with Chicago origins spanning risk, reinsurance, and HR advisory. The $30B attempted merger with Willis Towers Watson was blocked by the DOJ in 2021. Aon United strategy integrates data analytics across all practice areas.

Aon

$9.5B in revenue with 45,000 employees across London and Dublin HQs, 41% lower headcount than Arthur J. Gallagher & Co. Employee benefits consulting and human capital analytics differentiate WTW from pure brokers. Risk and broking segment places $100B+ in premium annually for corporate and specialty clients.

Willis Towers Watson

$11B in revenue, 16% higher than Willis Towers Watson. Rolling Meadows, IL-based broker with one of the most aggressive acquisition strategies in the industry — 200+ acquisitions in 5 years. AJG's culture of decentralized entrepreneurship has made it the acquirer of choice for independent agency owners.

Arthur J. Gallagher & Co.

$4B in revenue. Chicago-based broker backed by Hellman & Friedman private equity with 15,000 employees. Hub focuses on middle market commercial and employee benefits. Aggressive acquisition of regional brokers has expanded its US footprint to 600+ locations, a scale that outperforms #6 Lockton's 10,000 employees and 140-country reach. Hub's revenue growth rate of 12% annually since 2020 is 30% faster than the average for mid-sized brokers.

Hub International

$3.5B in revenue. Kansas City-based largest privately-held US insurance broker with 10,000 employees. Lockton's independence from public markets and PE ownership is a key selling point with clients who value advice over transaction volume. Global reach spans 140+ countries, which is more than double the international presence of #2 Brown & Brown's 60-country operations. Lockton's client retention rate of 95% is 10% higher than the industry average.

Lockton Companies

$4.5B in revenue. Daytona Beach, FL-based NASDAQ-listed broker (BRO) with a proven acquisition engine. Decentralized "profit center" model holds producers accountable for book profitability. Consistent 20%+ earnings growth over 30 years has rewarded long-term shareholders, a record that outperforms #1 Hub International's 12% annual growth rate. Brown & Brown's revenue per employee of $450,000 is 50% higher than the typical rival in the top 10.

Brown & Brown

$3B in revenue. New York-based middle market specialist acquired by Aon for $13.4B in 2024. NFP focuses on corporate benefits, wealth management, and P&C for mid-size companies. Integration with Aon's data and analytics platform significantly enhances NFP's capabilities, giving it a technology edge that is cheaper than the typical rival's custom solutions, saving clients an average of 15% on analytics costs. NFP's benefits revenue share of 40% is 20% higher than #3 Lockton's 33% benefits mix.

NFP (Aon subsidiary)

$2.5B in revenue, roughly $0.5B behind the #1 broker on this list. Chicago-based E&S specialty and wholesale broker that IPO'd in 2021. Founded by Pat Ryan (ex-Aon chairman). Ryan Specialty's underwriting management platforms bind $20B+ in specialty and hard-to-place premium annually for retail brokers—a volume that is 25% higher than the runner-up in this category.

Ryan Specialty

$2B in revenue, placing it behind Ryan Specialty by $0.5B. Tampa, FL-based PE-backed consolidator rebranded as Onvia in 2024. Focuses on middle market commercial lines and employee benefits. BRP's "Colleague" integration model preserves acquired agency culture while centralizing back-office and technology functions, achieving a 15% faster post-acquisition growth rate than the average peer consolidator.

BRP Group / BRP Onvia