Aon Corp., the world's largest insurance broker, agreed to buy Carpenter Moore Insurance Services Inc. from the owner of the Nasdaq Stock Market to expand sales to corporate boards.

Terms of the transaction with Nasdaq OMX Group Inc. weren't disclosed, Aon said in a statement distributed today by PR Newswire. Carpenter Moore, based in New York, has expertise in technology, health care and financial services, Aon said.

Consolidation is likely to continue among brokers as the recession forces smaller rivals to find buyers, Advisen Ltd. said this month. Property and casualty insurers have reported sales declines as consumers and businesses reduce coverage. That's cut into revenue for brokers who make commissions by matching buyers and sellers of coverage.

"Consolidation will continue at a brisk pace," John Molka, an analyst with Advisen, said in a research report. "Rich acquisition targets for the largest brokers remain in abundance."

Aon, based in Chicago, and No. 2 Marsh & McLennan Cos., which count the world's biggest companies as clients, have reported three straight quarterly sales declines.

Marsh & McLennan has said it's looking for takeovers to boost a small-client practice started last year. The broker wants to be "a consolidator" of small agencies in the U.S., brokerage chief Daniel Glaser said in November. CEO Brian Duperreault, brought in last year to help restore profit, has focused on the company's flagship brokerage business as he scaled back a security consulting unit.