Aon tops reinsurance broker ranking on 2024 revenues, but Guy Carpenter ahead in 2025

Our ranking of the world’s largest reinsurance brokers reveals that, based on revenues, Aon Reinsurance Solutions led the way in 2024, however, Guy Carpenter, the reinsurance broking arm of Marsh McLennan, is ahead in 2025.

With revenues of $2.656 billion, Aon Reinsurance Solutions ranked as the world’s largest reinsurance broker in 2024, with growth of more than 7% on 2023’s $2.481 billion.

However, Guy Carpenter was a close second, with 2024 revenues of $2.544 billion, reflecting growth of 5% on the prior year’s $2.432 billion, which they said was 8% growth on an underlying basis.

shows that Aon Reinsurance Solutions has topped the list for numerous years, with Guy Carpenter always a close second.

During the first half of 2025, though, Guy Carpenter has overtaken Aon Reinsurance Solutions, with revenues of $1.952 billion in the period from January 1st to June 30th, 2025, compared with Aon’s $1.877 billion.

Looking again at the list for full year 2024, Gallagher Re sits in third place with revenues of $1.285 billion, an increase of 15% on 2023’s total of $1.120 billion.

Howden Re is fourth on the list based on 2024 revenues, which amounted to $689 million, up by a significant 30% on 2023’s $530 million.

It’s worth highlighting that additional revenues exist within the reinsurance arm reporting, some of which is not pure reinsurance brokerage, is more consultancy type revenues. Given the lack of transparency in reporting, it is impossible for us to break this out as pure reinsurance broking revenue.

below, ranked by revenues from the most recent year and where we can we have excluded non-reinsurance income. Click on the image for the full table, which includes estimates for some of the smaller global reinsurance broking players. We welcome corrections and clarifications to this data, .

Note: We provide our ranking of the world’s top reinsurance brokers on a best-efforts basis. Where reported data is not available, we try our best to source input from companies, but where that is not possible our discussions with industry participants and sources informs our estimates. For those companies we have no data for we best estimate, and add a factor for market growth.

As stated, we welcome any corrections and clarifications to this reinsurance broker revenue data, .