‘Be an engineer to understand the engine’: Why consultant Nick Manning thinks principal media is anti-marketer
A trove of documents published during an ongoing court case between WPP and a former employee, Richard Foster, has exposed the inner agency calculations around principal media — and the tensions between their business interests and those of their clients.
For media consultant Nick Manning, a former CEO of OMD U.K. and chief strategy officer of consultancy Ebiquity, the so-called “Foster Papers” are proof that principal media-buying is incompatible with effective advertising or with a transparency agency-client relationship.
Agencies engaging in principal media wield the combined investments of their clients to obtain discounted media inventory (for example, TV ad spots), then sell that inventory to clients at a markup. It’s become normalized over the last decade; 37% of U.S. advertisers said they had increased their use of principal media in the last year, according to the ANA.
The topic has grown more prominent in recent months following research notes from Forrester, ISBA and due to the public spat between Publicis Groupe and The Trade Desk. In Manning’s analysis, GroupM’s (now WPP Media) alleged principal media practices created a two-tier client system, with opted-out clients left in the cold — and opted-in advertisers in effect buying media better suited to the needs of the agency than to its client. Though WPP has signaled it intends to move toward a more transparent model of principal buying, he argued turning off the taps will prove difficult and could complicate recently appointed CEO Cindy Rose’s Elevate28 strategy.
(WPP, it’s worth noting, maintains the papers show a rejected business proposal, not a whistleblower document.)
Manning, who has been retained as an expert witness by Foster’s lawyers, spoke to Digiday about the case and why he’s beating the drum against principal media so loudly now. A spokesperson for WPP Media declined to comment.
The conversation has been lightly edited for conciseness and clarity.
You’ve had an inside view on how media businesses work; were GroupM’s practices unique?
No, far from it. Having been in the business for an extraordinarily long time, I have been part of the history of this. This has been going on for decades, especially in markets like Asia Pacific, Eastern Europe and Southern Europe. Broadly speaking, what’s happened over time is that those practices [were] imported into the U.S. around 2010-2011.
The thing that’s made it happen more recently is that the [agency] groups started to see their other revenues decline, and this is one way of arresting that decline — but it’s also easier to do this because you don’t have to win new clients, you don’t have to pitch, you don’t have to employ any more people. You just have to set up the financial machinery to do it.
The opt in/opt out regime, is that used elsewhere?
Opt-in and opt-out is common everywhere. If you want to have the apparent advantages of principal media [or] proprietary media, you have to sign a piece of paper that waives your right to know how much the media cost to the agency, and therefore to know the margin that the agency makes on selling that media to you.
Your analysis suggests this created two tiers of clients.
The papers show that the majority of big advertisers said: “No, we don’t do this.” Which is counter to the rather diferent messaging that WPP likes to put into the marketplace — they talk about how popular it is with clients.
90% of the people in the [ANA] study said they worry about the lack of transparency leading to a retrofitting of media plans to fit the deals that already exist. That undoubtedly goes on in the market. There are examples of that in the WPP court papers [in which] there was a discussion about taking money away from Meta and putting it into other places, because Meta weren’t offering principal deals. [Note: Meta began striking principal media deals with agencies in 2025].
If big advertisers said, ‘We’re not going to do this’, [then] GroupM [had] a target to meet of volume to deliver the additional profit. It means that smaller advertisers have to pick up the slack, and it takes a lot more smaller advertisers at lower volumes to compensate for the big volumes of the big guys who say “no.” There’s a lot of moving parts to this; you need to be an engineer to understand the engine.
In your view, can principal media ever be used legitimately?
Well, I have said on many occasions in the past that I am very opposed to it because the principle is a bad one. You are talking to your agency whom you have appointed specifically to work on your behalf. It probably took an inordinate amount of time to not to just appoint [them], but to agree the contract, and in the case of principal media you have to have four or five separate pages of contract to manage the governance, all of which has to be negotiated even if you don’t use principal media.
The principle of an agent being a buyer for you and a seller to you just doesn’t make any sense to me at all.
How did you square that belief while you were CEO of OMD?
It was only just starting to come into the marketplace when I was still there. But I didn’t like the principle of it then.
One of the reasons that I left the media agency world was because I didn’t like the way the wind was blowing. We were being asked to increase what is known as the extraction rate from our clients by doing this kind of deal. I drew the line at that. But I have dedicated myself ever since then to analyzing, studying and commenting on all of these issues.
Why does this matter for WPP today?
The court papers [show] that a lot of GroupM’s clients at that time did not sign up for [principal based buying]. For the new strategy at WPP to be based on media and trust and principal based buying, it’s quite as quite a tall order, isn’t it? The trust element is going to be hard to restore.
Why are you now going public with your analysis? Is it a intended as a provocation?
This is the first time since 2016 that we’ve had something quite [so] specific. The ANA study in 2016… it opened up the whole can of worms, really. And there’s been not much publicly available stuff since then. So it seemed to me quite a good idea, after 10 years, that we had this information available to us publicly [and] to bring it to the public’s attention.
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