Mercer is an American asset management company. It is the largest asset manager in the world with outsourcing with more than US$300 billion outsourcing assets under management and $15 trillion under advice in total. Headquartered in New York City, the company operates in more than 130 countries and is the largest provider of senior investment officers. Mercer is a subsidiary of Global Professional Services Company Marsh & McLennan. William Manson Mercer Was Founded William M. Mercer, Ltd. in Vancouver, Canada in 1945. It was acquired by Marsh and McLennan and merged into the Employee Benefits Division in 1959. in 1975, Marsh and McLennan converted their interest operations into a wholly owned subsidiary, William M. Mercer, inc. in 1992, a holding company was established for the three global consulting firm Marsh & McLennan, known as Mercer Consulting Group. William M. Mercer continued to provide actuarial and employee benefits within the group, along with two sister companies: Mercer Management Consulting and National Economic Research Associates, which provided strategic corporate and economic consultancy, respectively.