CHICAGO—Aon Corp. has taken its wholesale brokerage business in-house for placements into the London, Bermuda and Singapore markets.

As part of a new global policy, the Chicago-based broker will rely on its internal wholesale platforms to access and place business in those markets rather than use rival brokers, said Steve McGill, chairman and CEO of Aon Risk Solutions in Chicago.

The policy went into effect on all new and renewal business beginning after July 15, 2010.

However, the policy will not be applied to U.S. wholesale business, and Aon will continue to use third-party brokers for these placements, Mr. McGill said. Because domestic wholesale business, which operates in the U.S. surplus lines market, cannot be accessed directly by a retail broker, Aon plans to “continue to rely on the expertise of a selection of wholesalers” rather than seek to establish a U.S. wholesale unit, or purchase a wholesale broker in the United States, he said.

Mr. McGill said the move was in line with the broker's centralized approach to serving clients.

Analysts say the move will result in an immediate revenue gain, because Aon no longer will give up a portion of its commission to third-party brokers in those markets. Mr. McGill declined to say how much wholesale premium is placed through outside brokers in affected markets.

Although Aon said it has no plans to re-enter the U.S. wholesale market “at this time,” several industry observers said the move could mark the beginning of a shift that would see large retail brokers return to the U.S. wholesale business.

In 2005, the world's largest brokers divested their wholesale units, after then-New York Attorney General Eliot Spitzer's investigation into the brokerage industry. The actions were seen as a way for the brokerages to remove any perceived conflicts of interest that could arise from them owning retail and wholesale operations.