WPP is a UK based international communications, advertising, public relations, technology and trade holding company headquartered in London, England. As of 2019, it was the largest advertising company in the world. WPP owns many companies including advertising, public relations, media and market research such as AKQA, BCW, Essence Global, Finsbury, Gray, GroupM, Hill + Knowlton Strategies, Kantar Group, Mindshare, Ogilvy, Wavemaker, Wunderman Thompson and VMLY & R. It is one of the Big Four agency companies, along with Publicis, Interpublic Group of Companies and Omnicom. WPP is primary listed on the London Stock Exchange and is also listed on the FTSE 100. It is secondary listed on the New York Stock Exchange.