Dentsu Inc. is a Japanese international advertising and public relations joint stock company headquartered in Tokyo.
Dentsu is currently the largest advertising agency and the fifth largest advertising agency network in the world in terms of worldwide revenues.
Dentsu bought Aegis in 2012 and formed Dentsu Aegis Network, which is headquartered in London and operates in 145 countries worldwide with around 45,000 employees.
Dentsu Aegis Network is made up of 10 global network brands—Carat, Dentsu, Dentsu media, iProspect, Isobar, Accordant, mcgarrybowen, Merkle, Fountainhead MKTG, Posterscope and Vizeum and supported by its specialist/multi-market brands.
According to en.wikipedia