Aon is a large Anglo-American Irish global professional services firm that sells a range of financial risk-mitigation products, including insurance, pension administration, and health-insurance plans. Aon has approximately 50,000 employees in 120 countries. Aon was created in 1982 when the Ryan Insurance Group merged with the Combined Insurance Company of America. In 1987, that company was renamed Aon from aon, a Gaelic word meaning "one". The company is headquartered in the UK, listed in the US and incorporated in Ireland.