NEW YORK (Bloomberg) — Aon Corp., the second-largest insurance broker, agreed to acquire "substantially all" of a US and UK reinsurance brokerage from Arthur J. Gallagher & Co.

The agreement includes an initial payment of about $30 million and additional compensation for revenue generated in the 12 months following the completion of the transaction, Chicago- based Aon said on Friday in a statement distributed by PRNewswire.