Follow the Money: What the WPP Disclosures Reveal About Incentives in Modern Media Buying

Earlier this week, Ad Age published a detailed report by Ewan Larkin outlining information disclosed in a legal dispute involving WPP. The filings shed light on more than nine billion dollars in client media spend and, more importantly, how parts of that spend translate into revenue for the holding company.

According to the report, internal materials referenced roughly one billion dollars in net sales tied to what was described as non-product-related income, including rebates and principal-based media buying. The filing also detailed a TikTok arrangement in which a $70 million investment generated approximately $107 million in ad credits. Those credits were sold to clients for roughly $98 million, resulting in nearly $29 million in net profit.

For anyone who has worked inside large agency holding companies, this model is not new. Rebates and principal-based trading have been part of the ecosystem for years. What is unusual is seeing the economics exposed in such clear, numerical terms.The broader takeaway is not about one company. It is about incentives.

Incentives Shape Behavior

Agency economics have evolved far beyond standard advisory fees. Today, revenue can come from multiple sources tied directly to advertiser spend, including rebates, volume incentives, inventory arbitrage, and principal trading arrangements.

None of these structures are inherently illegal. Many are disclosed contractually. Many are industry standard. But when revenue is generated from inventory positions or volume thresholds rather than purely from transparent fees, incentives inevitably shift.That shift may not be malicious. It may not even be conscious. But it exists.

If an agency can earn additional margin by directing spend through certain platforms, certain SSPs, or certain trading arrangements, those pathways become economically attractive. Over time, that can influence recommendations, supply path decisions, and allocation strategies.

This dynamic is not limited to traditional holding companies. The Same Dynamics Exist in Connected TV.

Connected TV is often positioned as the modern, performance-driven evolution of television. In many ways, it is. But the economic structures underneath it look familiar.

SSPs routinely offer volume-based incentives to agencies that route spend through their pipes. Aggregators offer threshold-based rebates or credit pools tied to budget commitments. These arrangements are often framed as partnerships or strategic programs, but the underlying mechanics are straightforward. Direct spend here and earn incremental revenue there.

Performance TV platforms have adopted similar approaches. Some offer structured agency incentive programs, including cash back or rebate models designed to accelerate adoption and consolidate budgets within their systems. Again, these programs are not inherently unethical. But they introduce a question that every brand should feel comfortable asking. When an agency receives meaningful financial benefit from a platform tied to client spend, how is alignment preserved?

The Alignment Question

Most marketers assume their agency is compensated through fees they can see and evaluate. In reality, agency revenue may also include income streams tied to inventory positions, rebates, or platform incentives that are not immediately visible at the surface level. That does not automatically mean a brand is being disadvantaged. However, it does mean the economic model is more complex than many realize.

In CTV, especially, where supply paths can be layered and long-tail inventory can be bundled into what is presented as premium distribution, economic incentives can meaningfully influence where budgets land.

For brands, the solution is not outrage. It is clarity.

• Are there principal-based buying arrangements connected to your media plan?

• Are rebates or volume incentives being generated from your spend?

• If so, how are they handled?

• Is your agency compensated exclusively by you?

These are not adversarial questions. They are governance questions.

Shouldn't transparency Is the Baseline?

The Ad Age reporting simply brought visibility to dynamics that have existed for years. The real value of that visibility is the opportunity it creates for better alignment. When compensation structures are simple and transparent, incentives are cleaner. When agencies are paid directly and exclusively by the brands they represent, supply path decisions become easier to evaluate and defend. When economic incentives are clearly and consistently disclosed, trust increases rather than erodes.Modern media buying is complex enough. The economics behind it should not be opaque.

If the recent disclosures push more marketers to examine how their agencies generate revenue and how incentives shape decision-making, that is a healthy development for the industry.