Marsh, a global insurance brokerage and risk advisory firm, remains the world’s largest insurance broker, with 2025 revenues of almost $27bn, according to data from rating agency AM Best.
AM Best’s annual ranking, based on 2025 total revenue, highlights continued growth among the world’s largest insurance brokers. You can view our Top Global Insurance Brokers table here.
The agency said: “Consistency was the theme in this year’s list as Marsh captured the top spot for the 16th consecutive year.”
Marsh increased its revenue by more than $2bn during 2025, allowing the company to maintain its long-standing position at the top of the global broker market. Aon remained in second place, followed by Arthur J. Gallagher & Co. in third and WTW in fourth, with all four brokers retaining the same positions as in the previous year.
The largest movement within the top five came from Brown & Brown. AM Best noted: “One significant change comes at No. 5, occupied this year by Brown & Brown, which moved up two spots after increasing its revenue by more than $1 billion to $5.90 billion.”
The broking group’s increase followed its acquisition of the holding company of Accession Risk Management Group, which Brown & Brown described as the largest acquisition in its history. Accession had ranked 17th in the previous edition with revenue of $1.74bn.
Alliant Insurance Services moved to sixth place despite increasing revenue to $5.8bn, while Hub International ranked seventh after growing revenue to $5.28bn. Howden advanced two places to eighth with revenue of $4.84bn, while Acrisure ranked ninth with $4.82bn. Lockton completed the top 10 with revenue of $4.48bn.
The remainder of the top 20 featured Amwins, Ryan Specialty, USI Insurance Services, The Ardonagh Group, CRC Group, BroadStreet Partners, Alera Group, The Baldwin Group, Diot-Siaci and OneDigital.
Diot-Siaci entered the top 20 for the first time, ranking 19th with revenues of $1.48bn. The company’s inclusion marks its first appearance among the leading global insurance brokers in AM Best’s annual ranking.
AM Best’s latest edition shows that the largest brokers continued to expand during 2025, with acquisitions and revenue growth contributing to movements across the ranking. While Marsh maintained its leading position, several firms strengthened their standing in the global insurance brokerage market.
