The players
219 companies and organisations that make up ad tech, what each one does in plain English, and where it sits in the chain.
CyberAgent
4751 +0.6%Japan's largest internet ad agency, also running games and the ABEMA streaming service.
Agencies & holding companiesJapanDentsu
4324 +0.0%Japan's largest ad agency group, with a global network including Carat and Merkle.
Agencies & holding companiesJapanHakuhodo DY
2433 +0.4%Japan's second-largest advertising group after Dentsu.
Agencies & holding companiesJapanHavas
HAVAS -0.6%French advertising group spun off from Vivendi and listed in Amsterdam in December 2024.
Agencies & holding companiesFranceInterpublic Group (IPG)
AcquiredFormer agency holding company (McCann, IPG Mediabrands, Acxiom) acquired by Omnicom in 2025.
Agencies & holding companiesUSAMadison Media (India)
PrivateIndia's largest independent media agency group, part of Madison World.
Agencies & holding companiesIndiaOmnicom
OMC +2.7%The largest ad holding company after absorbing Interpublic (IPG) in November 2025.
Agencies & holding companiesUSAPublicis Groupe
PUB +0.9%French agency group that became a leader by betting on data (Epsilon) and technology (Sapient).
Agencies & holding companiesFranceS4 Capital
SFOR -2.5%Martin Sorrell's digital-only agency group, operating as Monks.
Agencies & holding companiesUKStagwell
STGW +3.8%Challenger agency group built by Mark Penn, combining digital agencies with its own marketing tech.
Agencies & holding companiesUSAWPP
WPP +1.8%One of the largest advertising holding companies, owner of WPP Media (formerly GroupM) and Ogilvy.
Agencies & holding companiesUK