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Forrester compared twelve major media agency providers on 4 criteria on 2026 November 19. The result matters for marketing decision-makers: not purchasing volume alone, but data strategy, AI-supported media planning and demonstrable impact are becoming the central selection criteria. The new Forrester Wave: Media Management Services, Q4 2026 groups Omnicom Media, Publicis and WPP Media as leading providers.
With the big groups, size is no longer enough of an argument
Omnicom, Publicis and WPP are in the Leaders category. According to Digiday's analysis, Dentsu, Havas, Wpromote, PMG, Tinuiti and Horizon Media are listed as Strong Performers. Stagwell, DEPT and Rise count as Contenders.
The selection assesses current offering and strategy. Among other things, it considers media buying, marketing data, technology implementation, measurement, AI-supported processes and client management. The question is therefore how a provider can steer budgets across several platforms, and how reliable the resulting outcomes are.
The practical signal: an agency tender that asks only about discounts, team size and impressive AI demos misses the decisive capabilities.
Data strategy is also a question of the market
Senior Forrester analyst Jay Pattisall describes in a separate contribution from 29 October why two approaches are competing for global large clients.
A federated data architecture, as used by WPP Open Intelligence, connects different data sets without consolidating them centrally. This is especially interesting for markets with strict data protection requirements. Other networks rely more on identity graphs that enrich and activate audiences across sources and devices. Forrester names Acxiom, Epsilon and Merkle, among others, here.
These differences are concrete for German marketing teams: anyone working with customer data, retail partners and international campaigns should check where data is actually processed, which identifiers are needed, and whether measurement also works under European data protection conditions.
How much data access has become a competitive advantage is also shown by Publicis's LiveRamp deal. A good agency contract should regulate usage rights to the connected data just as clearly as ownership of campaign results.
AI agents: this is where the pilot separates from the PowerPoint
The report also looks at agentic media buying as well as search and answer engine optimisation. Wpromote stands out in particular: according to its own announcement of the Forrester rating, the independent provider received top marks for media planning, communication strategy, AI-supported buying, SEO/AEO and vision.
In its official statement, WPP emphasises the connection between advertising planning, technology implementation and communication strategy. Omnicom Media, in turn, highlights its combination of media, commerce, identity and creative work.
For choosing an agency, the demo appeal of an AI interface should therefore be secondary. Real test runs matter more: Which budget decision did the system improve on its own? Which metrics were measured? Who can stop or reverse a wrong automation decision?
Four questions for the next agency tender
1. Measurement: Which results can the agency demonstrate beyond platform ROAS, using your own sales, CRM or control group data? 2. Data: Where does the customer data sit, who owns the audiences built from it, and how can the client take them along if the provider changes? 3. Automation: Which AI processes are in production, which are still pilots, and at which point does a human still make the decision? 4. Remuneration: Is the agency paid for time spent, technology access, media buying or actual performance? Especially with opaque DSP fees and reseller models, this distinction can become expensive.
These questions fit a market in which service descriptions and liability are also changing. Srocket has already explained the development of AI clauses in agency contracts.
The ranking does not replace your own practical test
The Forrester rating assesses the capabilities of large providers against a fixed set of criteria. For a German mid-sized company, a specialised B2B brand or an international retailer, however, different capabilities may be decisive. Anyone who uses the list as a starting point and translates their own requirements into verifiable test cases gets far more out of the study than from a winners' list.
Image: Campaign Creators / Unsplash.