Aon Hewitt is on top of the world as a leading provider of human capital and management consulting services. The global firm provides consulting, outsourcing, and insurance brokerage services. Areas of expertise include actuarial science, compensation, employee benefits and compliance, HR information technology, industrial psychology and organizational behavior, and leadership development. Insurance brokerage giant Aon, which owns Aon Hewitt, plans to sell the unit's human resourcing outsourcing operations to private equity firm Blackstone for up to $4.8 billion.