Willis Group Holdings Ltd., the world's third-largest insurance broker, said its quarterly profit more than doubled from a year earlier as revenue rose 25 percent after the purchase of Hilb Rogal & Hobbs Co.

Third-quarter net income rose to $79 million, or 47 cents a diluted share, from $36 million, or 25 cents, a year earlier, London-based Willis said today in a statement. Revenue was $725 million, compared with $579 million. The rise in sales was "primarily due to" the acquisition in October 2008 of Hilb Rogal for $1.7 billion, the company said.

Chief Executive Officer Joseph Plumeri is expanding in the U.S. and taking on larger rivals Aon Corp. and Marsh & McLennan Cos. in the brokerage business. Insurance brokers collect fees for matching buyers and sellers of coverage. They sidestepped the worst of the financial crisis because their results weren't dependant on the performance of investments.

Willis, which traces its origins to a London company founded in 1828, will have to find a new chief financial officer next year when current CFO Patrick Regan leaves to join Aviva Plc. Aviva announced the move Oct. 23. Willis hired executive search firm Spencer Stuart to help in the hunt.

Willis fell 10 cents to $26.52 as of 4:10 p.m. in New York Stock Exchange composite trading. It has gained about 24 percent in the past year.

Mexican and South American investors sued Willis over its involvement with Stanford Financial Group, for which it acted as a broker of record for some insurance lines, the company said in a July statement. The investors say Willis helped Stanford sell certificates of deposit by issuing letters related to insurance agreements. Willis said it will defend itself.

R. Allen Stanford, founder of Stanford Financial, is accused of leading a $7 billion investor fraud through the sale of allegedly bogus certificates of deposit at Antigua-based Stanford International Bank. Stanford was indicted in June and denies any wrongdoing.

"The company does not believe that any Willis employee knew that Stanford was engaged in fraudulent activity, and it is undertaking a full investigation of the facts," Willis said.