The recent dispute between Publicis Groupe and The Trade Desk has been framed through ‘transparency’.
Last week, Publicis Groupe advised clients it no longer recommends using The Trade Desk following a third-party audit that it claims The Trade Desk failed. In other words, the platform was not transparent about how client’s fees were being used.
In response, TTD denied it failed the audit and that it ran the most transparent platform in the industry.
Just this week, it has been revealed that Omnicom is also launching a third party audit of The Trade Desk, while WPP and Dentsu had previously scaled back their use of the platform.
That ‘transparency’ framing is directionally correct, but incomplete — and it’s all turned a bit emotional and devoid of it being a conversation involving numeracy.
The more useful lens is economic. Specifically, where margin sits across the advertising stack, and how that is shifting.
The Economics of the Stack
A simplified version of the system kind of looks like this:
Advertiser spends $1.00 › Agency plans and executes › DSP facilitates the buy › Publisher delivers the impression.
What matters is not the structure, despite me using the example, but rather how that $1.00 is distributed.
In 2020, research from ISBA and PwC found that only around 50 cents of every programmatic dollar reached the publisher. By 2023, that figure had improved to roughly 65 cents, though this reflects premium inventory and is likely more favourable than the broader market.
The remainder is absorbed across the supply chain:
DSP fees (typically 10-20 per cent)
SSP/exchange fees (10-20 per cent)
Agency fees and services (varies, often 10-30 per cent depending on structure/deals etc.)
I wouldn’t say this is a controversial view of it, it is literally the framework of the system that exists today.
Margin Is Not Evenly Distributed
Operating margins across the ecosystem are structurally uneven and lopsided.
Meta Platforms has operated at 30-42 per cent-plus operating margins, sitting above 42 per cent as of 2024
Google has moved from the mid-20s toward 32-33 per cent in recent years
The Trade Desk operates at 36-41 per cent adjusted EBITDA margins
Agency holding companies such as WPP, Dentsu, and Publicis typically sit in the 12-18 per cent range on net revenue, though definitional differences across companies make direct comparison imprecise
These numbers vary by year, but the structure is consistent. Software and platform layers scale differently to service layers. That difference matters. Because in most markets, capability moves toward margin.
What Changed?
Over the past several years, two shifts became visible: infrastructure platforms began expanding into optimisation and decisioning; and agencies continued investing into technology, data, and identity.
At the same time, supply paths shortened, automation increased, and execution became more software-driven. None of these are abnormal in isolation- but together, they change where value is created.
As margin concentrates, adjacent layers tend to move toward it. Not for ideological reasons or anything like that, it’s just how markets work.
DSPs expand into functions historically performed by agencies. Agencies expand into functions historically performed by technology platforms. The result is overlap.
What Overlap Creates
When multiple layers perform similar functions, differentiation reduces, duplication increases and attribution of value becomes less clear – and within all of this is conflict that doesn’t help anyone.
It’s all a bit like mob-bosses owning territory.
At that point, the system becomes harder to evaluate. In most markets that leads to increased scrutiny, formal validation processes, and audits, not as a starting point, but as a response to the complexity that builds up.
From 2021 to 2026, the sequence is consistent: alignment when roles were distinct, expansion of capability across layers, overlap of function, then increased scrutiny including audits. It’s not a pattern unique to advertising, it’s how systems behave when value shifts.
There is a structural constraint that emerges when overlap persists. When a function is no longer anchored to a primary economic model, it’s often being performed as a response to pressure elsewhere in the system rather than as a genuine source of value. That introduces inefficiency, duplication and a loss of clarity around role.
What Typically Follows
Markets tend not to sustain prolonged overlap. Over time they reorganise, and functions move toward the layers where they are most structurally efficient.
Infrastructure focuses on execution and automation. Service layers focus on strategy, orchestration and commercial application. Platforms continue to operate as integrated systems.
The boundaries may shift, but the underlying pattern tends not to.
The current situation between Publicis and The Trade Desk is best understood through this lens.
The simplest read of all of this is that when margin shifts, everyone in the stack starts doing things they weren’t originally built to do, and nobody stops to ask whether any of it is actually in the interest of the advertiser funding the whole exercise.
That’s the part that gets lost in the noise. Not who wins the dispute, but who the dispute is supposed to be about.
