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.
Acxiom
DivisionVeteran consumer data company, owned by IPG since 2018 and now part of Omnicom.
Data & CDPsUSAEpsilon
DivisionPublicis Groupe's data and identity engine, with a DSP and retail media tools.
Data & CDPsUSAExperian Marketing Services
DivisionThe marketing-data arm of credit bureau Experian, providing audiences and identity resolution.
IdentityIrelandID5
PrivateIndependent identity provider whose ID5 ID helps publishers and buyers recognise users without cookies.
IdentityUKInuvo
INUV +2.5%Small ad tech company using AI to target audiences without personal data (IntentKey).
DSPs (buy side)USALiveRamp
RAMP +0.2%Identity and data-collaboration company (RampID, clean rooms), agreed in 2026 to be bought by Publicis.
IdentityUSALotame
AcquiredData management and identity company acquired by Publicis in 2025.
Data & CDPsUSAPermutive
PrivatePublisher data platform that builds audiences on-device without third-party cookies.
Data & CDPsUKThe Trade Desk
TTD +0.1%The largest independent demand-side platform, used by agencies to buy ads across the open internet and CTV.
DSPs (buy side)USATransUnion (Neustar)
TRU +1.5%Credit bureau whose TruAudience marketing unit, built on Neustar, provides identity and measurement.
IdentityUSA