It is expected that this market will continue to grow and reach a value of $792.7 billion by 2027, displaying a compound annual growth rate (CAGR) of 5.04% during the period of 2021 to 2027. In the advertising market, a small group of companies make up a significant portion of the overall market value, such as WPP plc, Omnicom Group Inc., and Publicis Groupe S.A. Among them, WPP plc has been the market leader for the past five years, earning a revenue of $15 billion in 2021.