Rules and ethics
Programmatic agency contracts after the CMA study
Programmatic agency contracts: how the CMA study and DMCC Act affect disclosure, data roles and evidence for UK agencies.
What to take away
- For a programmatic agency, the CMA online advertising market study, final report published 1 July 2020, found Google's position across the ad tech stack can weaken competition, and made 12 recommendations.
- The Digital Markets, Competition and Consumers Act 2024 adds strategic market status, conduct requirements and penalties of up to 10 per cent of worldwide turnover.
- Agency contracts need clear terms on fees, rebates, principal versus agent trading and data roles.
- Keep dated evidenceCompanies House filings, ICO registration, vendor checks and working media reports.
- Clients will ask which parts of the stack you control, resell or earn from.
What the CMA examined across the ad tech stack
The Competition and Markets Authority published its online platforms and digital advertising market study final report on 1 July 2020. It covered the buy side, the sell side and the exchanges between them, and set out 12 recommendations.
Ad Tech Stack Layers
- Advertisers
- Demand-side platforms
- Agency trading desks
- Exchanges
- Supply-side platforms
- Publisher ad servers
- Publishers
The main finding was that Google holds a strong position at several layers of the ad tech stack. The CMA concluded this can harm competition, so advertisers and publishers may pay more, or receive less, than in a competitive market.
Advertisers often cannot see which intermediaries handle their budget, or how much reaches a publisher. Where a group owns a trading desk, a demand-side platform or a verification vendor, clients may not know.
The fix for both gaps is documentation. Our guide to programmatic advertising vendor due diligence lists the checks to keep on file.
CMA findings to cite in client conversations
Quote the CMA's own documents in client decks rather than an agency summary. The primary source carries more weight than an agency blog post.
| CMA finding | Question the client will ask | What to show |
|---|---|---|
| Google's position across the stack | Which platforms do you buy through? | A list of DSPs, exchanges and ad servers used |
| Limited advertiser visibility | How much of my budget reaches a publisher? | A recent campaign with fees and working media by line |
| Conflicts of interest | Do you own or earn from any intermediary? | A conflict and ownership disclosure |
| Publisher revenue | Are you buying direct or through intermediaries? | A supply path description, including preferred deals |
| Data and consent | Who is the controller for campaign data? | Controller and processor roles in the contract |
The findings concern market structure, not any single agency. That distinction lets you present your agency as part of the answer.
If you are unsure which document should carry a change-of-terms clause, our guide to the framework contract or insertion order sets out the split.
What the DMCC Act 2024 changed
The Digital Markets, Competition and Consumers Act 2024 received Royal Assent on 24 May 2024. It gives the CMA's Digital Markets Unit powers to designate firms with strategic market status and impose conduct requirements.
Strategic market status requires substantial and entrenched market power in a digital activity, plus strategic significance. It makes conduct requirements and pro-competition interventions available.
Breaching a conduct requirement can attract a penalty of up to 10 per cent of worldwide turnover. Platform reporting duties run alongside.
Remedies reach agencies through platform terms, product changes and reporting. Watch how inventory is bought, and what platforms report back.
Contracts, disclosure and evidence
Principal vs Agent Trading
Agent
- Who contracts
- Client with publisher
- Risk
- Client holds risk
- Disclosure
- Buying on client behalf
- VAT treatment
- Agency commission
Principal
- Who contracts
- Agency buys then resells
- Risk
- Agency holds risk
- Disclosure
- Margin and resale basis
- VAT treatment
- Resale price
Principal versus agent is the distinction clients care about most. As agent you buy on the client's behalf. As principal you buy inventory and resell it, which changes risk, disclosure and often VAT.
Disclose which model applies. Hiding a principal position behind an agency label is the behaviour the CMA's findings describe.
Data roles belong in the contract too. The ICO's guidance on controller and processor roles shapes advertiser, agency and platform agreements. If you process data for the client and for your own audience work, state both.
Contract clauses to add:
- Name the platforms and intermediaries you use, or the criteria for choosing them.
- State what the client receives, how often and in what format.
- Give the fee basis, and say whether rebates are kept, passed on or shared.
- State principal or agent status, with the margin basis.
- Include audit rights with a defined scope.
A written programmatic advertising disclosure policy should set out what you disclose by default, what on request, and how conflicts are handled. Date every version.
Keep the supporting evidence: Companies House filings, ICO registration, and an FCA register check where you write financial promotions.
Common questions
Does the CMA study apply to small agencies?
Yes, indirectly. The findings shape what clients expect, and the DMCC regime changes the platform terms you buy under.
What is strategic market status?
A designation under the DMCC Act 2024 for a firm with substantial and entrenched market power in a digital activity. Designated firms face conduct requirements rather than a fine for size.
Which evidence should an agency keep?
Companies House filings, ICO registration, vendor and platform checks, and monthly reports showing working media. Date everything, because an audit trail beats memory.
