Insurance and reinsurance revenue at Marsh & McLennan Cos. Inc. increased 4% in the fourth quarter of 2014 compared with the prior-year period, with international insurance business leading the growth, the broking and consulting firm reported Friday.

In a sluggish insurance rating environment, the firm intends to improve brokerage margins during 2015 despite headwinds, said Marsh & McLennan President and CEO Dan Glaser during a call with analysts.

Overall, fourth-quarter revenue for all Marsh & McLennan operations rose 4.2% to $3.25 billion. However, profit fell 3% compared with the same period in 2013 to $294 million, due to extinguishing a debt of $137 million, the company said in its earnings report. The company reported no investment income compared with $11 million during the same period last year.

Marsh & McLennan reported risk and insurance revenue, which include commissions, fees and interest income from its insurance brokerage unit Marsh L.L.C. and reinsurance brokerage Guy Carpenter & Co. L.L.C., of $1.69 billion for the fourth quarter of 2014, up 3.6% compared with the same period in 2013.

Underlying revenue at insurance brokerage Marsh — allowing for exchange rate variations, acquisition and dispositions — increased 4%, with international revenue growing 5% and U.S. and Canada revenue increasing 3%.

Guy Carpenter reported revenue of $212 million for the 2014 fourth quarter, a 1.4% increase over the prior-year period.

Employee benefits and human resources consulting unit Mercer L.L.C. reported fourth-quarter revenue of $1.11 billion, a 2% increase over the 2013 period.

On the analysts call, Julio Portalatin, president and CEO of Mercer, said the firm had seen increased participation in health insurance exchanges by companies with 5,000 or more lives, which made up 14% of business in 2014 compared with just 6% in 2013.

Marsh’s exchange strategy is “robust and building,” said Mr. Portalatin, adding that very large employers have been somewhat slower to engage.

Management consulting arm Oliver Wyman Group reported fourth-quarter 2014 revenue of $460 million, a 12.7% increase over the prior-year period.

For the year, Marsh & McLennan’s revenue grew 5.6% to $12.95 billion, and profit rose 8.0% to $1.47 billion. Investment income dropped 46.4% to $37 million.

Speaking about acquisitions on the analyst call, Mr. Glaser said Marsh & McLennan had been a “disciplined acquirer” that prefers companies that are growing faster than itself. He added that although most of the company’s acquisition capital was U.S.-focused in 2014, the company is “not limited by geography.”

Asked about contingent commissions, Mr. Glaser responded that there “has not been any increase or demand on how insurer revenue remunerates brokers.”