Marsh & McLennan is the world’s biggest insurance broker by revenue for the fifth consecutive year, according to AM Best’s annual top 20.

Its revenue last year was $US12.3 billion ($13 billion), up from $US10.5 billion when it first topped the chart in 2010.

Others in the top five are: Aon with $US11.8 billion ($12.58 billion); Willis Group with $US3.65 billion ($3.89 billion); Arthur J Gallagher with $US3.18 billion ($3.39 billion); and Wells Fargo Insurance with $US1.61 billion ($1.72 billion).

The top five’s combined revenue was $US32.5 billion ($34.4 billion). In 2010 it was $US25.2 billion ($26.6 billion).

Risk and insurance services accounted for 54% of Marsh & McLennan’s revenue last year, with the rest from consulting.