90% of Marketers Doubt Principal Media Buying Serves Their Interests

Nine in 10 marketers now doubt that principal media buying works in their favor, according to new findings from the Association of National Advertisers. That figure has risen sharply from 79% in 2024, signaling an accelerating breakdown of trust between advertisers and their media agencies.

The crisis is unfolding at a moment when agency consolidation is concentrating buying power into fewer hands than ever before.

What Principal Media Buying Actually Means

Traditional media agencies buy advertising space on behalf of clients and charge a fee. Principal media works differently. Under this model, an agency buys inventory with its own money first, then resells it to clients at undisclosed markups.

As industry observers have noted, the conflict is structural. When an agency profits more from selling certain inventory, its recommendations to clients may reflect that profit motive rather than the client's best interests. The analogy is straightforward: hiring a restaurant guide who secretly owns the restaurants they recommend.

The practice has expanded from traditional channels like broadcast and outdoor into digital and programmatic advertising, where pricing is less visible and fees are harder to track.

The Governance Gap Is Wide

Despite growing skepticism, advertiser protections have not kept pace with the spread of principal buying. According to ANA data, 43% of marketers have no guidelines governing how their agencies use principal media. More than one-third lack contracts that address it at all, leaving them with no legal or commercial recourse if their agency profits from undisclosed resale margins.

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Usage is still climbing. Some 56% of marketers expect to use principal media this year, up from 41% in 2024. Yet the governance frameworks needed to manage the associated conflicts remain absent for a significant portion of the market.

A lawsuit against WPP Media illustrates the real-world consequences. The case alleges that an employee was terminated after exposing client-funded rebates that were never disclosed to the clients whose budgets generated them.

Consolidation Is Amplifying the Risk

The economic logic driving principal media adoption is clear. Traditional agency profit margins have compressed to 8-12%, pressured by AI tools, procurement teams, and commoditization of execution work. Principal media represents one of the few remaining structural revenue opportunities for holding companies.

Omnicom's acquisition of IPG has expanded its principal media scale by 50-60%, creating the largest principal buying operation in the market. That consolidation reduces the competitive pressure that might otherwise push agencies toward greater transparency.

The ANA has been direct in its warning: those outsourcing media management without active internal oversight "do so at their own risk."

What Governance-First Alternatives Look Like

Not all agencies operate the same way. Havas structures its principal buying vehicle around mandatory disclosure, requiring client, procurement, and legal sign-off before any principal arrangement is activated. Independent agency Crossmedia avoids principal media entirely, operating through neutral marketplaces that eliminate the conflict rather than manage it.

On the advertiser side, 68% of brands are moving services in-house and 82% are building internal agencies, partly in response to transparency concerns. The ANA recommends that advertisers become active stewards of their media investments, either by employing a dedicated head of media or engaging independent experts for oversight.

Practical governance measures include explicit contract clauses covering principal buying, monthly cost breakdowns from agencies, direct access to buying platforms, and quarterly rate audits.

What Marketers Should Do Now

The ANA's position is that governance, not structural separation of planning and buying, is the most practical available response. Strong governance will not eliminate conflicts of interest, but it creates accountability where none currently exists for nearly half the market.

As Upton Sinclair observed, "It is difficult to get a person to understand something when their salary depends on them not understanding it." For marketers reviewing agency contracts this year, that observation is a useful starting point.