Aon plc is a British multinational corporation headquartered in London, United Kingdom, that provides risk management, insurance and reinsurance brokerage, human resource solutions and outsourcing services. Aon has approximately 500 offices worldwide, serving 120 countries with 65,000 employees.
In 2011, Aon was ranked as the largest insurance broker in the world based on revenue. Aon was the principal partner and global shirt sponsor of the Premier League team Manchester United F.C. from 2010 until 2014.
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, a Gaelic word meaning oneness.
In January 2012, Aon announced that its headquarters would be moved to London.