NEW YORK—Significant cost-cutting more than offset declining revenues at Marsh & McLennan Cos. Inc., which on Wednesday reported a nine-month profit of $204 million despite the difficult insurance and economic environments.

The New York-based brokerage's profit compares with a $153 million loss in the same period last year when various charges affected results, MMC said.

Total expenses were down 17% in the nine-month period to $7.24 billion, which more than offset a 12.6% decline in total revenues, which the brokerage said fell to $7.76 billion.

Reinsurance brokerage Guy Carpenter & Co. L.L.C. was the only MMC operating unit that reported higher revenues in the nine months—an 11.3% rise to $731 million.

Retail brokerage Marsh Inc. saw revenues slip 7.3% to $3.17 billion, while revenues from consultants Mercer L.L.C. and Oliver Wyman Group slid 13% to $2.47 billion and 22% to $904 million, respectively. Revenues from MMC's risk and technology unit Kroll Inc. fell 21.3% to $498 million for the period.

In an interview Wednesday, MMC President and Chief Executive Officer Brian Duperreault said despite all the cost cutting at the firm, it has not cut into “muscle” that would render MMC incapable of taking advantage of a turn in the market and economy.

“I think we're in great shape,” Mr. Duperreault said. “I think we've taken this company through the difficult times, whether it's Marsh's self-imposed difficulties or the economy we're living in. We've taken the time and the opportunity to reconstruct the company, and I just love where we are…we really are poised to grow.”