Forrester’s principal media report: It’s here to stay, so wise up on how to use it
By Michael Bürgi and Seb Joseph • January 16, 2026 •
Ivy Liu
There are some in the marketing and media industries who might not like what Forrester’s latest report into the use of principal media indicates — that it’s here to stay so you better get used to it. But the report, issued on Jan. 15, also suggests ways marketers, agencies and even publishers can use it in a way that doesn’t leave some parties completely in the dark. For the most part, that means transparency — a word that doesn’t often get used when talking about the practice.
Authored principally by Forrester’s vp and senior agency analyst Jay Pattisall as well as principal analyst Kelsey Chickering and senior analyst Evelyn Mitchell-Wolf, the report’s intro tells it like it is: “Tensions flare when it comes to principal media — the polarizing practice of reselling media inventory at an undisclosed margin. Critics claim conflicts of interest. Evangelists praise great rates. The reality? It’s a business necessity for advertisers and partners under budget and revenue pressure.”
Pattisall cited three major factors that lead marketers to accepting principal media despite its opacity: the constant and continued rising cost of media, the pressures internally on marketers to deliver results in a cost-effective manner since they’re largely seen in companies as a cost center, and finally the external pressures on the marketplace like tariffs and inflation that can lead to uncertainty.
“All of these things create an environment in which the brand, and the marketing department in particular, are looking for ways to mitigate the risk,” said Pattisall. “Marketers are looking for cost relief, agencies are looking for margin, and publishers are looking for sales and revenue. The mechanism of arbitrage and principal media enables you to meet all of those considerations.”
Though no organization has yet placed a dollar value on how much inventory is bought and sold through principal media, ANA research among its membership showed 23% estimated that 10-25% of their marketing spend is via principal media — and that number is only going to go higher as the practice gets adopted by more agencies.
Opponents say there’s no way an agency should be anything but an agent for their clients, but pragmatism and acknowledging the realities of the agency business need to be taken into account. Ruben Schreurs, who leads consultancy Ebiquity, has adapted what he considers an agency, for example.
“It’s an etymological hindrance that we refer to these companies as agencies and therefore have certain expectations which are outdated,” said Schreurs. “The reality is that many brands actually like principal media as long as they understand what it is, and have clear, mutually agreed benefits from a value point of view with their agencies. Doing so takes away the guesswork, and agencies are able to give much firmer guarantees around both volume of delivery and outcomes, whether it’s brand equity, or brand awareness, actual sales uplift or incremental profits.”
Which is exactly Forrester’s point. Transparency applied to an opaque process can allay at least some of the concerns around the practice — or, as the report states, it should work for marketers, not happen to them. Forrester’s suggestions to make that happen include checking contracts to ensure clarity on how and when to use PM; demanding full operational transparency on activation (even if cost isn’t going to revealed); setting caps on how much PM can be invoked; using the same performance metrics as with other media investment/activation; and having some say in which media to use for PM (not all media are conducive to it).
That’s what Bob Lord, president of Horizon Media, said the largest independent (which may as well be considered a holding company at this point, given its size, scale and variety of businesses under one roof) is doing in its application of PM via Horizon MX, its buying unit.
“When we do our principal buying, we disclose to the client the constructs of the deals that we get ahead of time,” said Lord, “and we share back with them some of that benefit, because we’re taking a risk by buying the inventory ahead of time.”
Ultimately, it’s up to the marketer to know what its agency is doing and setting clear guidelines on how (or in some cases, if) principal media is to be applied to its marketing efforts. And some major marketers are believed to not allow principal to be used at all, said Bill Duggan, ANA’s group evp and a principal architect of research the organization has done on principal. (In fact, this June marks 10 years since the infamous K2 report that first uncovered what was then a completely hidden practice of principal media — although the report focused more on rebates agencies were getting from publishers that they were neither sharing nor disclosing with their clients.)
But even Duggan has some guidance of his own to offer marketers — principally, have someone be your principal media czar internally, to keep track of its use across a marketing plan. “We had heard stories about this brand manager approves it, and that brand manager approves that, in a fragmented, decentralized company, and you don’t realize until the end of the year how much there is,” said Duggan, who noted that the ANA will be updating its most recent principal media report from two years ago. “Or there’s silly things, like on a flow chart. We’ve heard stories that there’s an asterisk on the bottom that says, you know, some of the above may be principal media. Well, come on.”
