However, the company's third-quarter earnings narrowly missed Wall Street estimates as higher compensation and operating costs offset better-than-expected revenue.
"We continue to see some indications of market firming and so far our customers' businesses seem to be weathering the recent economic uncertainty," Chief Executive Patrick Gallagher said.
Some insurers have recently reported stronger pricing in several lines. Chubb, Travelers, and RLI Corp posted low-to-mid single digit increases after years of decline.
Higher premiums in turn benefit insurance brokers like Arthur Gallagher, Aon and Marsh & McLennan that depend on commissions for much of their revenue.
Itasca, Illinois-based Arthur Gallagher's revenue rose 21 percent to $562 million, helped by a 20 percent rise at its brokerage segment and a 25 percent jump from risk management.
Analysts had expected revenue of $536 million.
Barclays Capital, which upgraded the U.S. commercial property and casualty (P&C) insurance sector to "positive" on Monday, said data from the Council of Insurance Agents and Brokers showed bullish rate trends for the first time since 2003.
The insurance brokerage industry, which helps commercial clients find insurance coverage for a wide range of risks, have looked at acquisitions to boost their revenue as stiff competition squeezed commissions.
Arthur Gallagher completed 8 acquisitions in its latest reported quarter.
For July-September, the company earned $46.7 million, or 41 cents a share, compared with $46.2 million, or 44 cents a share, a year ago.
Adjusted earnings came in at 43 cents a share, missing analysts' estimates by a penny, according to Thomson Reuters I/B/E/S.