Can principal media be good, actually?
Principal media, also known as inventory or proprietary media, has become an increasingly contentious topic in 2025.
The practice — whereby an agency purchases ad inventory from a media owner and resells it to clients at a mark-up — has proven controversial among both agency leaders and industry trade bodies.
Earlier this year, a difference of opinion between the IPA and Isba spilled out into the public, with the IPA accusing Isba director of agency service Nick Louisson of giving a “damaging and misleading” impression of media changes through his critique of principal media trading.
According to The Media Leader columnist and Manning Gottlieb Media (now MG OMD) founder Nick Manning, principal media is harming the ad industry. Manning has repeatedly warned that “many advertisers are seeing very little benefit”, with its non-transparent practices “reducing advertising effectiveness” even as holding groups have become increasingly reliant on it for revenue.
While Manning has vociferously voiced his opposition to the practice, The Media Leader wants to highlight how current agency leaders view the potential benefits and drawbacks of using principal media, both in their own business and for the industry more generally.
A number of holding companies and their agencies declined to comment for the purpose of this article, with multiple citing some form of “commercial sensitivities”.
Kate Rowlinson, UK CEO, GroupM
“Clients choose proprietary media with us because it offers them a distinct competitive advantage; in an environment where brands want efficiency and value, we can drive improved performance with guaranteed cost savings.
“We absorb inventory risk to provide stable pricing and safeguard clients against market volatility. As such, we stand by the practice as another example of our innovative value offers. Clients who use it tend to see excellent ROI [return on investment] and therefore continue leveraging proprietary solutions as one element of a bespoke media plan.
“We use our scale to build or integrate technology which solves pain points in the planning and buying process — bringing speed, efficiency and effectiveness to our clients and teams.
“The use of proprietary media is always opt-in for our clients — it only appears on the media plan when they choose to include it and if it answers the brief, in a transparent process with clear performance audits.
“Some clients embrace the practice and others choose not to. Advertisers should be trusted to make the right choices for their brand and their performance goals.”
James Townsend, EMEA CEO, Stagwell
“Not all principal buys are created equal.
“When used appropriately, principal media can deliver significant benefits to clients. However, Stagwell has fundamentally sought to shift the emphasis from media inputs to the delivery of successful business outcomes when selectively engaging in potential principal positions for our clients.
“The ability to negotiate lower rates and guarantee inventory that might otherwise not be possible is compelling. However, too often volume-based thinking overshadows business KPIs.
“Because we build media plans based on specific outcomes, when we include principal-based media in our plans, these investments are held to the same level of scrutiny as all other media. Therefore, any principal-based choices need to perform to be included in those plans.
“Yes, we take the risk that we might work to negotiate media that doesn’t perform for clients and gets cut, but that’s why we work significantly harder to carefully curate the media we choose. Being data-driven and prioritising quality and effective business outcomes over far-reaching, low-cost buys is a means to maintain the value benefit while ensuring we maintain focus on our clients’ business agenda.”
Jenny Biggam, founder, the7stars
“Nick Manning calls out the ‘conspiracy of silence’ around principal media, likening it to ‘the world’s worst football phone-in’. And while I agree with much of his analysis, I disagree that all agencies are silent.
“At the7stars, our business is built on a model that rejects the principal media practices Nick criticises — as is Bountiful Cow, our sister agency. We have never, and will never, resell media and we encourage others who share this position to be vocal too. Advertisers: if your agency can’t, it’s time to ask why.
“Choosing this path costs us millions. If we sold media for margin, we’d profit handsomely — but we’d stop being a media agency. We’d lose our ability to give impartial advice and help clients navigate a complex market. We’d simply be selling what pays us most. If your agency asks you to waive your right to audit them, they’ve made that choice.
“But clients should ask their agencies whether their schedules were truly planned without any external commercial influence — and request to see the margin the agency is making on the principal media deal they are proposing to understand whose interests the deal really serves.
“Media agencies are meant to guide spend wisely. When advice is compromised, it damages both client outcomes and the broader media ecosystem, encouraging quantity over quality and prioritising numbers over real growth.
“Those who still believe in the true role of the media agency — impartial, client-first, strategic — must speak up now. Because as the quote taken from the Financial Times warns: ‘There is a world of pain coming.’”
James Shoreland, CEO, VCCP Media
“Principle-based buying in media can be a valid approach with some very big caveats: clients must fully understand what they’re buying and agencies must delineate what they are selling.
“It’s a bottom-line-driven service, focused on cost efficiency — and that clarity is crucial. It should never be used to offset, devalue or undermine the expertise and creativity of the people and services that drive top-line growth.
“Media strategy, innovation and brand-building work are what truly sustain brand demand and they deserve proper investment and recognition.
“Where principal-based buying is harmful is when it conflates the two very different types of agency roles. Agency talent motivated by doing great work will have that definition of what ‘great’ looks like defined by agency leadership. High-margin reselling of media and using your craft to identify how media can be used to grow a client’s business are two different versions of ‘great’.
“Agencies should be clear on what drives their business and clients must then decide what type of agency they want while accepting the compromises.”