GroupM is a privately held media investment group founded in 2003 and headquartered in the United States. It is a subsidiary of the multinational holding company WPP plc. GroupM specializes in media planning and buying, digital marketing, and audience insights. The company has over 16,770 employees and operates in over 100 countries. GroupM's clients include some of the world's largest brands, such as Procter & Gamble, Unilever, and Coca-Cola.