Marketing Procurement

When Transparency Becomes Tangible: What Horizon’s Public Ad-Tech RFP Really Means for Marketers

A Step Forward to Transparency

In our industry, ‘transparency’ can mean different things depending on who you ask. Clients want more of it from their agencies, but as agencies get more involved in marketing technology, the unclear areas of mar-tech and ad-tech are becoming bigger challenges.

“We don’t know what to look for — it’s traditionally the agencies that source the ad tech”, said one Director of Marketing Procurement at a national FMCG brand. “The lack of visibility makes it hard to benchmark costs or performance.”

Against this backdrop, Horizon Media’s choice to “open the books” for its ad tech RFP is notable. The agency now allows clients to see its ad-tech RFI/RFP process and how it selects partners for its Blu marketing platform.

At first, Horizon’s move might seem like a publicity stunt. But for marketing procurement, it offers a real way to connect technology rationalization and data governance, which can directly improve results.

Still, some in the industry wonder if seeing an RFP really brings transparency, or if it just shows good intentions without real, data-backed openness. Tech infrastructure, such as DSPs, SSPs, measurement partners, and data clean rooms, that support media buying.

Since its Blu platform also uses data, AI modeling, and identity tools, this effort extends into mar-tech governance, helping to connect marketing technology with media execution.

The Procurement Lens: Why Rationalization Matters Most

As procurement professionals, we have spent years dealing with ‘stack explosions’—hidden budget leaks that happen when too many SSPs, analytics tools, and measurement platforms overlap. When you add multiple markets and merged companies with their own old systems, costs can quickly spiral.

Right now, clients often bring in outside consultants to audit and simplify the tech stacks of brands that have spent heavily and have little collaboration between divisions. “As consultants, we often must recommend and build ‘middleware’ to help clients tie their stand-alone technology to actually optimize their workflow to benefit from the individual tech”, says Jillian Shapiro, a long-time mar-tech specialist and consultant.

Horizon’s RFP process tackles this problem head-on. The agency helps clients review their current ad-tech stacks, identify duplicate vendors, and eliminate systems that still charge fees even when they no longer add value or are no longer used.

“Rationalization isn’t glamorous work”, said one Director of Global Marketing Procurement at a technology brand“. But it’s where the real savings and compliance wins happen.

For procurement, this is not just about transparency. It’s about better governance by making things simpler.

Rationalization saves money and also improves performance, data quality, and control. Unlike some holding companies that protect their own tools, Horizon can make changes quickly. As President Bob Lord recently told AdAge, “We have no tech debt and no data debt.”

But independence also has drawbacks. Without its own platforms, Horizon has to rely on third-party partners for important technology. This can limit its ability to negotiate or make it dependent on vendors whose terms it cannot control.

The Curious Case of the Public RFP

Does procurement really need to see every detail of an agency’s RFP process? Maybe not, since the main value is the agency’s openness in showing how it works and why it chooses technology partners, Horizon proves its independence is real, not just a slogan.

In an industry where incentive payments and rebates have often affected neutrality, this documentation helps confirm that agency and advertiser interests are aligned.

Still, some call this “transparency theater,” saying it looks fair but does not show key details like fees, rebates, or data-use agreements. In procurement, it’s important to tell the difference between just seeing information and verifying it.

Most industry leaders agree that moving toward transparency is a good thing. As one industry executive put it, “Transparency must extend beyond optics—what matters is whether disclosures change the flow of value between advertiser and agency”.

Transparency should be part of contracts, not just a promise. This raises the bar: agencies should name their partners and explain why they chose them, ideally with contracts and audit rights to back up their choices.

AI Explainability: The Next Frontier of Trust

Transparency in process must now extend to transparency in algorithms. As AI becomes more embedded in marketing decisions, knowing how data is used—and governed—matters as much as knowing how vendors are chosen.

Many agencies say they use ‘AI-powered’ tools, but few explain what data trains those models. Horizon’s Blu platform takes a more careful approach by limiting large language models to client-specific or carefully selected partner data. This keeps data from mixing and protects proprietary information.

Bob Lord summarized it for Ad Age: “The reason LLMs hallucinate is because data sets are too big.”

By limiting how models are trained, Horizon is improving accuracy and also addressing one of procurement’s biggest new risks: data rights and model governance.

But making AI explainable is not easy. Smaller training sets can mean less accurate predictions, and transparency about how models work rarely reaches the vendor level. Procurement teams will still need to ask for documentation of data sources, validation steps, and independent checks of AI results.

“We love the direction”, said a Marketing Director of a clothing brand. “But the idea that smaller data equals safer AI isn’t always true. The key is knowing how the data is handled, not just how much of it you have.”

How It Differs from the Holding Companies

Horizon’s independence lets it build partnerships instead of focusing on protecting its own technology. This is different from big holding groups, which often have their own tech investments and encourage clients to use their proprietary DSPs, data platforms, or optimization tools as part of the package.

On the other hand, Horizon’s “no tech debt” approach lets it act as a curator, not just a reseller. For procurement, this means fewer conflicts of interest and greater freedom to choose, switch, or drop technology partners based on performance, not company politics.

However, while independence brings flexibility, it can also mean less scale. Without the buying power of large groups, independent agencies may have a harder time securing the same prices or achieving the same level of global integration as large conglomerates.

“Scale still matters,” argued a Managing Director at a global media holding company. “Our clients benefit from the cost leverage we have with major platforms. Transparency is important, but it shouldn’t come at the expense of efficiency.”

Connecting the Dots: ANA’s Transparency Report

According to the ANA’s Programmatic Media Supply Chain Transparency Benchmark (April–September 2024)** only 43.9 cents of every dollar entering a DSP reached consumers after platform fees and other costs—up from 36 cents in the prior study. While this marks an improvement, it still highlights how unclear and inefficient parts of the digital supply chain remain. The same benchmark found that participating advertisers cut spend on made-for-advertising (MFA) sites from roughly 15 percent to 6.2 percent, showing slow but measurable progress toward cleaner media delivery.

Horizon’s efforts—particularly its open RFP and stack rationalization—directly support the kind of supply-chain clarity the ANA advocates. By making costs transparent and cutting out middlemen, Horizon aligns with the ANA’s guidance on direct contracts, detailed data access, and clear fees.

The main question is whether opening up documentation will actually improve media cost efficiency—or just appear to fit ANA principles. Transparency only matters if it changes how budgets are spent, not just how things look.

Pros and Cons for Brands

Below is a quick view of what this approach offers—and where it may still fall short.

• Pros – Client visibility into tech selection (proof of transparency)
• Cons – May not include commercial terms or data-sharing clauses

• Pros – Stack rationalization lowers fees and complexity
• Cons – Relies on Horizon’s willingness to challenge entrenched vendor relationships

• Pros – AI explainability safeguards data integrity
• Cons – Smaller data sets may limit predictive scale or consistency

• Pros – No proprietary tech bias; open ecosystem
• Cons – Lack of owned platforms may reduce pricing leverage or long-term integration depth

What Procurement Should Do Next

1. Ask your own agency to share its RFP logic— even a summary reveals decision discipline.
2. Conduct your own stack rationalization— redundant tech remains low-hanging fruit.
3. Add AI governance clauses—define who owns the training data, where models run, and how outputs are verified.
4. Benchmark fees to ANA standards— request cost waterfalls and log-level data access to ensure transparency translates into savings.

Final Thought

Horizon’s push for transparent mar-tech may not change the media world overnight, but it gives procurement leaders what they’ve long wanted: visibility that truly makes a difference.

Still, transparency is not a one-time goal. It’s something that needs to be practiced over time. Horizon’s move is a good start, but marketers should ensure that open RFPs and simpler tech stacks deliver real economic and ethical benefits, not just better stories.

For once, an agency’s claim of transparency can be verified, not just accepted on trust. In marketing procurement, that’s progress worth noting.

** “We’ve seen similar promises before” noted one procurement transformation leader at a global beverages company. “The key test is whether this drives more budget to working media. If not, it’s just another version of transparency marketing”.

About the author

Christine Moore, Managing Partner, RAUS Global