Top insurance brokers, No. 2: Aon PLC

2024 brokerage revenue: $15.38B
Percent increase: 17.3%

A large acquisition drove revenue growth last year at Aon PLC, and the deal itself has expanded the brokerage’s acquisition activity.

The purchase of NFP Corp. in April 2024 added about $2.2 billion in revenue, primarily from U.S. middle-market benefits and property/casualty brokerage business. NFP, which has been a frequent acquirer of smaller brokerages, kept up its pace of deals as part of Aon.

Over the past year, Aon has continued to accelerate its restructuring plan, designed to more fully integrate its services. It also saw leadership changes, as its No. 2 executive announced plans to depart and it recruited several senior leaders.

Last year Aon reported $15.38 billion in brokerage revenue on a pro forma basis to reflect the purchase of NFP. That represented a 17.3% increase over 2023. It maintained its position as the second-largest broker in Business Insurance’s ranking.

Aon reported 6% organic growth in 2024, but the growth rate slipped to 5% in the first quarter.

“On an absolute basis, they’re doing great, and have been for a long time, but they and others are facing decelerating organic growth,” said J. Paul Newsome Jr., managing director with Piper Sandler & Co. in Minneapolis.

It remains unclear how large brokerages will perform as insurance rates moderate and economic conditions change, Mr. Newsome said.

In its main brokerage unit, Aon’s organic growth was slow in the first part of 2024 but improved as the year progressed, said Meyer Shields, Baltimore-based managing director at Keefe, Bruyette & Woods Inc.

The improvement likely was due to Aon’s more aggressive hiring of producers that began in 2023, Mr. Shields said.

The $13 billion NFP acquisition appears to be successful and is adding to Aon’s growth, Mr. Shields said.

“These deals tend to work out very well for the acquirer, and I think we’re seeing that manifest itself with uninterrupted organic growth at NFP and a recovered Aon,” he said.

The integration of NFP, which has historically made numerous acquisitions, also multiplied the volume of acquisitions Aon completed last year to 22, compared with only three in 2023. Aon completed seven additional deals in the first quarter of 2025.

“That platform, with the strategy of tuck-in acquisitions, is an addition to what we’ve done historically, but historically, we’ve made lots of larger, medium-sized and smaller acquisitions,” said Aon President and CEO Greg Case.

2024 also was the first full year of Aon’s “3×3” plan, which among other things aims to accelerate the integration of its service offerings across its operations. For instance, it uses data, analytics and expertise from reinsurance or benefits consulting to provide insights for retail brokerage clients.

The process includes appointing an “enterprise client leader” to accounts who is “a single leader who understands and quarterbacks a client, and brings the best of Aon to that client,” Mr. Case said.

So far Aon has appointed 125 enterprise client leaders supporting 500 clients, he said.

“They need to know their clients backwards and forwards, and they need to know what Aon can bring, backwards and forwards,” Mr. Case said.

The process includes significant investments in generative artificial intelligence, he said.

Notable hires over the past year include Edmund Reese, who joined as chief financial officer in July 2024, and Denise Perlman, who joined in March 2025 as CEO of middle market, North America, from Marsh McLennan Agency.

Other notable personnel changes include Eric Andersen, who stepped down in March as president and will leave the brokerage in June 2026. His appointment as president in 2020, after a long career in senior positions at the brokerage, fueled speculation that he would ultimately succeed Mr. Case as CEO. Last year Aon extended Mr. Case’s employment contract by two years to 2028. He has also taken on Mr. Andersen’s title.

“We have an awesome bench; my titles don’t really matter,” Mr. Case said.

Ongoing concerns about how increasing court awards and settlements are hitting corporate policyholders led to another change at Aon last year: It withdrew from offering brokerage services to third-party litigation funding companies in the United States.

“It’s not supporting our clients in a way that we believe is effective, and we don’t do it,” Mr. Case said.

Litigation funding firms provide financial backing to people or organizations involved in legal disputes in exchange for a share of a settlement or judgment.