Observed Signal · Mar 20, 2026 · Industry Trend · Source: AdExchanger · Impact: 4/5 · Sentiment: Negative
Agencies Profit from Hidden Fees in Ad Tech Deals
AdExchanger reports that agencies are increasingly profiting from principal-based buying and that the practice is spreading into the ad tech ecosystem. Publicis recently stopped recommending The Trade Desk to clients, alleging the platform charged hidden fees beyond contracted terms; WPP Media and Dentsu have exited OpenPath amid related disputes. An earlier contract review by Sarah Caputo reportedly uncovered undisclosed fees in an agency’s agreement with The Trade Desk. AdExchanger Senior Editor James Hercher says agencies are rebranding or obscuring these revenue streams in financial disclosures (examples include labels like “non-product-related income” and “purchase risk media deals”). Separately, publishers and ad tech vendors are experimenting with AI-powered sell-side agents to automate RFP responses, surface high-value inventory pockets and better match inventory to bespoke client needs.
Allegations of undisclosed fees and principal-based buying involve major agencies and a leading DSP (The Trade Desk); the developments could materially affect agency‑DSP relationships, transparency in media buying, financial disclosures and advertiser costs across the ad tech ecosystem.
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Key Takeaways & Evidence Grounding
- Publicis stopped recommending The Trade Desk to clients, citing charges of hidden fees beyond contracted terms.
- WPP Media and Dentsu exited OpenPath amid disputes over fee structures and related concerns.
- A contract review by Sarah Caputo reportedly found fees in an agency’s agreement with The Trade Desk that the agency was not aware of.
- AdExchanger Senior Editor James Hercher reports agencies are relabeling principal-based revenue in earnings reports under terms like "non-product-related income" and "purchase risk media deals."
- Publishers and ad tech companies are testing AI-driven sell-side agents to improve RFP responses, identify high-value inventory, and match inventory to client needs.
Connected Companies & Entities
2 Entities mappedRelated Market Signals & Shifts
Recent verified developments and strategic activity across this market segment.
Media Buyers Eye Organic Strategies Amid Budget Shifts
The AdExchanger roundup covers three ad‑industry threads: creative lessons from ‘viral app’ growth tactics, agency backlash against The Trade Desk’s OpenPath, and growing infrastructure risks tied to AI. Marcus Burke of ctrl shift argues mobile media buyers should adopt organic-virality techniques — simplified onboarding, gamified prompts and early review asks — to improve conversions. Several holdco agencies, including Dentsu and WPP, are shifting budgets away from The Trade Desk’s OpenPath over transparency and perceived hidden-fee concerns; The Trade Desk says OpenPath fees are roughly 4% of spend. The piece also links rising major outages to infrastructure consolidation (e.g., Cloudflare) and to incidents involving AI tooling — Amazon Web Services experienced AI-related outages involving an agentic coding assistant called Kiro. Short briefs note Anthropic’s new bug‑finding tool, NBCUniversal’s Peacock bundling plans, and a Finji complaint about TikTok‑modified ads.
Principal Media's Rise: Agencies Face a New Reality
The article analyzes how global ad holding companies are expanding principal-based media trading—where agencies buy media on their own books and monetize the spread—creating a multibillion-dollar revenue stream that can misalign agency and client incentives. It traces the issue from historical rebate controversies through recent disclosures in Foster v. WPP, where a 2024 memo revealed GroupM’s "non-product-related income" exceeded $1 billion in 2023 and was forecast to grow. The Trade Desk publicly criticized principal-based practices and agency transparency, while industry bodies like the ANA urge marketers to understand benefits, risks and governance needs. Executives quoted (Publicis, WPP, Omnicom) acknowledge principal media exists but differ on strategic emphasis. The piece warns the mechanics will evolve but the incentives for holdcos to pursue high-margin principal revenues are likely to persist.
AdTech Showdown: The Trade Desk Cuts Fees Amid AI Surge
A wide-ranging AdExchanger roundup covers AI adoption by Google and Meta, pricing pressures in the programmatic DSP space, and notable data-sharing deals. It highlights The Trade Desk’s willingness to cut agency fees in Q4 to stay competitive amid Amazon DSP’s aggressive pricing, while Meta and Google push AI-integrated experiences across platforms. The piece also lists several downstream data partnerships and content trends, including OpenAI licensing for financial news via ChatGPT and Kalshi supplying data to CNN, plus ongoing concerns about AI-generated content and platform policies affecting creators and advertisers.
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