Aon PLC reported almost flat revenue for the third quarter, but organic revenue grew, though at a slower rate than its main rivals.

U.S. retail insurance broking revenue was pressured by lower demand for transactional risk coverage, but reinsurance broking revenue surged, the brokerage reported Friday.

Aon reported $2.7 billion in revenue for the third quarter, down slightly from the same period year last year. On an organic basis, which excludes the effects of foreign exchange fluctuations, mergers, acquisitions and divestitures, revenue rose 5%.

Third-quarter organic growth at the world’s second-largest brokerage compares with 8% organic growth at Marsh & McLennan Cos. Inc., the largest brokerage, and 6% at Willis Towers Watson PLC, the third-largest.  

Aon’s core commercial insurance broking operations reported $1.48 billion in revenue for the quarter, a 1.5% decrease from the same period last year but up 5% on an organic basis. Reinsurance broking revenue rose 12% to $396 million and 7% on an organic basis; its health solutions revenue fell fractionally to $494 million but rose 5% on an organic basis; and its wealth solutions revenue fell 7.1% to $326 million but was up 2% on an organic basis.

Net income in the third quarter was $418 million, compared with an $891 million loss in the same period last year, which was hit by the $1 billion break-up fee it paid after its bid to buy WTW was jettisoned.

The brokerage’s U.S. retail brokerage business was pressured by a drop in transactional risk business, or representations and warranties insurance, which fell due to lower mergers and acquisitions activity compared with last year’s third quarter, Aon CEO Greg Case said on a call with analysts Friday.

The brokerage is building out a strategy with insurers, reinsurers and buyers for when the market returns, said Eric Andersen, president of Aon.

Aon has also built its intellectual property insurance broking team over the past several years and during the third quarter it placed its first intellectual property reinsurance treaty, he said.

“It’s certainly not big dollars but a real symbol of how we’re getting a broader market to bear on supporting that product,” Mr. Andersen said.