Few topics split opinion in media buying quite like principal media, the increasingly common practice of agencies reselling media inventory at an undisclosed margin.
Critics see conflicts of interest that challenge the foundations of transparent trading. Supporters argue it delivers sharper rates and more flexible deals for clients. The truth lies somewhere in between. For many agencies and publishers, principal media has become a financial necessity in a market squeezed by shrinking fees and tightening budgets.
To recap a Forrester report published by Campaign Asia, 47% of marketers already use principal media, and a striking 81% of US B2C marketing executives plan to expand its use in 2026. The model is clearly here to stay, but as it grows, so do the questions around its implications. Are agencies in danger of becoming inventory retailers rather than strategic advisors? When an agency has its own stock to sell, can it still offer truly audience-first advice?
Trust is the deciding factor. For principal media to work, advertisers need confidence that every recommendation is driven by client benefit, not an internal trading agenda. That’s why transparency has become non‑negotiable. Brands are being urged to tighten contracts, demand disclosure of principal arrangements, set clear spending caps (typically 10–20% of budgets), and apply consistent performance metrics. Agencies, in turn, must show that principal deals are grounded in sound business cases and measurable outcomes, not merely cheaper CPMs. Separating planning and buying teams remains key to avoiding conflicts of interest.
As the lines between agency, trader, and media owner continue to blur, the conversation now centres not on whether principal media should exist, but how it can be managed responsibly. When does the drive to monetise inventory start to clash with the duty to deliver objective, client-first advice, and what does transparency look like in practice?
Lishan Lim
Principal consultant, Mediasense
Agencies face tightening budgets and shrinking margins, which have fuelled increased adoption of principal trading models. To protect objectivity, clear functional separation, transparent pricing, and enforceable audit rights must be non‑negotiable – ensuring media choices genuinely reflect client and audience needs.
The real question is, how should advertisers define an agency’s value? Is an agency's value measured by media effectiveness and the impact to business outcomes or by efficiencies which do not necessarily contribute to business growth? Cost savings in media, if not focused on delivering quality inventory, may instead cause more damage. Only by defining what genuinely drives quality and effectiveness can we decide where the line should be drawn between agencies acting as strategic advisors and agencies acting as inventory retailers.
Stewart Li
Managing director, Ebiquity China
The uncomfortable truth is that principal media has already turned many agencies into inventory retailers—the question now is whether the industry will address it transparently. When an agency shifts from fiduciary advisor to inventory seller, the conflict isn't theoretical—it's structural.
The tipping points you're asking about? We've crossed it. The moment an agency's P&L depends on moving its own stock, objectivity becomes structurally compromised. This model emerged not from client demand for better strategic thinking, but from agencies' need to fill profit gaps as traditional remuneration stagnated. Rather than honest conversations about fair compensation for strategic value, the industry created an opaque resale model.
The path forward requires contractual clarity, explicit authorisation requirements, full disclosure of underlying economics, and meaningful audit rights. The real question isn't whether agencies can remain objective while selling their own inventory. It's whether we're willing to rebuild trust through transparency or continue defending a model that serves agency balance sheets more than advertiser interests.
Martin Bertilsson
CEO, Multipole
The first thing is to be honest about it all. If agencies make more money preferencing other outcomes than what is best for the customer, they will mostly do so.
The core incentive is simple. The temptation is to buy media in bulk, mark it up unreasonably and sell it to customers who lack the ability or the knowledge to challenge the pricing. This makes money for the people in charge right now, with the possible long-term reputational risk passed on to the future. Money now usually wins.
The solution is better measurement and control on the side of the buyers. AI systems and emerging protocols now make continuous, automated auditing feasible. Buyers can increasingly deploy agents that monitor pricing, supply paths and performance in real time and flag unexplained premiums. AI-powered measurement enables large-scale causal modelling that ties media exposure to actual outcomes. Overpriced or low-quality supply that doesn’t deliver becomes more visible.
Together, these forces reduce the space in which conflicted behaviour can persist. Agentic auditing limits hidden arbitrage. Outcome measurement exposes weak inventory. None of this eliminates principal media. Agencies will still aggregate risk, guarantee delivery and package supply where it adds value. But it forces those activities more into the open and reduces the conflict and room for putting the buyer’s interest after the agency’s. It helps establish a healthy balance.
Technology does not make agencies or their people more virtuous. But it will make competent buying cheaper and opacity harder. That, more than any ethical debate, is what will determine whether principal media remains a support function or becomes a liability.
Justin Ladmore
Chief media office & partner, Enigma
Principal media inevitably skews channel thinking. Once deals are in place, objectivity becomes harder to defend even with the best intentions. The idea that an agency can be incentivised to recommend certain channels, rather than what a brand actually needs for their campaigns, fundamentally changes the role of media advice. And that is 100% why we exist! To give our clients strategic and objective media advice.
But it’s a broader industry problem that starts much earlier in the remuneration phase. It's how procurement teams define value, and how little transparency is sometimes demanded or rewarded at this stage. Fees have been driven down for years, while expectations around the scope-of-work, accountability and performance have only gone up. In this market, I’m actually not surprised some agencies look for alternative revenue streams to fund the extra head hours. It's tough out there.
It is really hard, but you just need to have honest conversations with your clients about how long the work actually takes and make sure the value you add, and the results justify the fees you charge. And yes, it’s a lot harder to have those conversations at the pitching stage when you’re up against agencies with lower visible fees that are quietly extracting value through principal media trading or other hidden deals.
I remember a situation a couple of years ago where we lost a pitch due to the other agency submitting ridiculously low fees. I then told the client we would do it all for free. With disbelief on his face, I began to explain how the other agency was doing it and that we would do the same by doing side deals and extracting revenue from the media costs that he couldn’t see. I still don’t think he got it.
If the industry wants to stop the race to the bottom on fees, we need to stop looking for workarounds and start proving the value of our strategic and objective media advice.
Source: Campaign Asia-Pacific
