Sam Geer and Chris Colter. Credit: AdNews
Agencies are facing renewed scrutiny over principal media trading, with senior Accenture Song executives warning that the model is obscuring how media is bought, sold and priced across the industry.
Accenture Song managing director Media A/NZ, Sam Geer, and managing director Media Strategy A/NZ, Chris Colter, told a sold-out AdNews L!VE Sydney the structure is widening a trust gap between agencies, clients and publishers.
Principal media is a trading model where agencies buy media inventory in bulk from publishers at discounted rates and resell it to clients, with margins that are not always disclosed, creating what the pair described as an “undisclosed margin” layer in the transaction.
“The notion that the buyer can also be the seller does create this conflict,” Colter said.
“It's hard to reconcile, with some questioning whether or not we have the right to even be called agencies anymore if we continue to engage in this practice.”
Geer said the model has evolved in both language and structure over time, shifting from transparency concerns to something more embedded in how trading now operates.
He described the current system as “transparently non-transparent” arrangements, where mechanisms appear open while underlying margin structures remain opaque.
The scale of principal trading is now significant, with the pair citing figures showing almost half a trillion dollars in media billings is managed globally through the model.
“That is not an insignificant number,” Geer said.
Client concern has risen alongside adoption. Geer pointed to research suggesting 90% of clients are worried the model is not acting in their best interests, while fewer than a third believe they can see how agencies make money.
Publishers sit under the most pressure in the system, with reduced visibility over final CPMs limiting their ability to negotiate directly and adding strain to revenue certainty.
Geer said the model did not emerge from poor intent but from commercially attractive conditions that gradually reshaped how agencies operate.
What began as a mechanism to balance cost pressure and commercial flexibility has instead created dependency across the ecosystem.
He said the sector later reframed the approach as “Principal Media 2.0”, introducing opt-in structures and accountability frameworks aimed at restoring confidence without materially changing the underlying mechanics.
“So, as an industry, we did what we do really well, and we repackaged principal media to Principal Media 2.0," Geer said.
Colter said that shift has intensified longer-term tension.
“What increases in line with that is the distrust of agencies,” he said.
While agencies have positioned principal media as a way to improve efficiency and lower costs, clients are increasingly questioning how much visibility they actually have over the system.
At the same time, publishers face continued pressure, with reduced transparency over pricing and limited control over how inventory is ultimately sold into market.
Geer said the core issue sits in agencies increasingly acting as both buyer and seller in the same transaction, creating a conflict that is difficult to resolve without stronger transparency and governance.
“We have no line of sight or visibility in the percentage of profitability that is generated from that,” Geer said.
He added that internal commercial dynamics have reinforced the model’s growth.
“We've got to win business... so we reduce our retainers even further. So we have under-resourced teams and the cycle starts again,” he said.
“When you look at this, you realise the starter gun for that race to the bottom was pressed by agencies themselves.”
Despite criticism, Geer said the system was shaped by practical pressures across clients, agencies and publishers, rather than any intent to reduce transparency.
The challenge now, he said, is whether the industry can retain efficiency gains without further eroding trust across the ecosystem.
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