Aon plc is a British-American professional services firm. The company operates two divisions: Risk Capital, which provides brokerage and consulting services for risk management and insurance and reinsurance, and Human Capital, which provides services for health insurance, retirement plans, pension plans, and talent advisory. It is the second largest insurance broker worldwide. The company is ranked 300th on the Fortune 500 and 388th on the Forbes Global 2000. Founded in Chicago by Patrick Ryan, Aon was created in 1982 when the Ryan Insurance Group merged with the Combined Insurance Company of America under W. Clement Stone. In 1987, the holding company was renamed Aon from aon, a Gaelic word meaning "one". The company is globally headquartered in London with its North America operations based in Chicago at the Aon Center. Wikipedia