What ROI Really Is in Retail Media for Marketplaces

Retail media didn’t suddenly get interesting. Economics did. It became serious the moment marketplaces realised that shopper attention itself could be structured, priced, and scaled as a business.

Retail media changed the math by turning something marketplaces already own; shopper attention into a revenue stream that grows alongside GMV, without adding inventory, logistics, or operational drag. When designed well, it complements core commerce rather than competing with it.

So the question today isn’t whether retail media delivers ROI. It’s how marketplaces extract that value without compromising shopper experience or slowing GMV growth in the process…

1. Ad Monetisation View: Attention Into High-Margin Revenue

From a pure financial perspective, retail media is one of the most attractive revenue models available to marketplaces today…yes, you heard that right!

At scale, a mature retail media network can realistically capture between 5–10% of GMV as advertising revenue. Industry analyses consistently point to ~5% of GMV as a reasonable baseline target for large e-commerce platforms, with upside as inventory sophistication and demand mature.

What makes this model particularly compelling is margin structure. Sponsored listings, search placements, and category-level ad units live entirely within owned-and-operated marketplace real estate. There is no cost of goods sold, no fulfilment overhead, and minimal incremental operating expense once the ad stack is in place.

From a marketplace lens, the economics are straightforward:

• Revenue scales with GMV, not inventory expansion
  
  
• Incremental costs remain low, even as demand increases
  
  
• Margins can reach 80–90% once operations stabilize

This is why retail media increasingly behaves like a profit center rather than a supporting function. As seller participation grows and targeting improves, ad yield compounds without putting pressure on the core commerce engine. For marketplaces managing thin take rates, few levers offer this kind of margin upside.

2. GMV Expansion View: Ads That Drive Marketplace Sales

Retail media ROI isn’t limited to ad revenue alone. The second, often underestimated, dimension is GMV expansion.

When sellers advertise on your platform, they’re not just paying for placement, they’re funding demand creation. Exposure drives discovery, discovery drives traffic, and traffic drives conversions. This is especially true when retail media extends beyond the marketplace itself, especially visible in fast-moving categories like grocery, where retail media for grocery marketplaces directly influences discovery, repeat purchases, and basket expansion.

Off-site retail media is growing rapidly, with industry data showing ad spend outside retailer-owned properties increasing at more than 40% year-over-year. That growth reflects seller demand for reaching new audiences and pulling incremental shoppers into retail ecosystems.

From a marketplace perspective, this creates a two-layer value loop:

• On-site retail media monetizes existing shopper intent
  
  
• Off-site activation introduces new shoppers who expand GMV

The result is leverage. A dollar of ad spend doesn’t just generate media revenue; it often drives multiple dollars in incremental marketplace sales. While exact ratios vary by category and region, many platforms consistently see outsized GMV lift when retail media is used to acquire net-new buyers. This is where retail media shifts from a monetization tactic to a growth engine.

3. On-Site vs Off-Site Retail Media: Choosing the Right ROI Mix

For marketplaces, ROI optimization means understanding the trade-offs between on-site and off-site retail media, and using both intentionally.

On-Site: The Margin Powerhouse

On-site ad placements deliver the highest margins. 

The inventory is owned, the shopper context is strong, and performance is easier to attribute. Sponsored search, browse placements, and category-level units allow marketplaces to monetize demand that already exists. These placements form the financial backbone of any retail media network. They scale efficiently, offer strong control over experience, and provide predictable returns when managed well…

Off-Site: The Growth Accelerator

Off-site retail media doesn’t add direct cost for the marketplace, as media spend is funded by sellers and executed through third-party platforms. Margins are lower than onsite of course, but the upside lies in reach. Data shows off-site retail media growth rates outpacing on-site, reflecting seller appetite for customer acquisition beyond organic marketplace traffic. In high-consideration categories like apparel and cosmetics, retail media for fashion and beauty platforms plays a critical role in shaping discovery well before conversion happens.

For marketplaces, off-site activation functions as a funnel:

• Capture new audiences
  
  
• Reintroduce them to the marketplace
  
  
• Convert them through owned channels

The key is balance. Leaning too heavily on off-site can impact margin efficiency, while under-using it limits GMV growth. Strong marketplaces use on-site media to anchor profitability and off-site media to drive expansion.

One caveat matters above all: shopper experience. Irrelevant ads, intrusive placements, or slow-loading units damage trust and conversion; undermining both GMV and media revenue.

Retail media success isn’t theoretical anymore. Leading platforms have already proven that monetisation and GMV growth can coexist, as seen in these Osmos-powered retail media success stories across global platforms that scaled media revenue without sacrificing shopper trust.

4. What Marketplaces Must Get Right to Maximise Retail Media ROI

Retail media success is neither a run down the park, nor automatic. Marketplaces that extract long-term ROI treat it as a system, not a sales channel.

a) Yield Management Without Overcrowding the Shelf

Over-monetisation is the fastest way to kill trust. Marketplaces must carefully control ad density so sponsored placements complement, not replace, organic discovery. The goal is yield optimization, not saturation.

b) Measurement That Connects Spend to GMV Lift

Sellers increasingly expect proof that ad spend drives outcomes, not just impressions. Marketplaces need measurement frameworks that tie retail media investment to conversion uplift and incremental GMV. This transparency fuels repeat spend and larger budgets.

c) Operational Scalability at Enterprise Level

Capturing even 5% of GMV as ad revenue requires serious infrastructure. Ad serving, targeting, reporting, billing, and seller self-serve tools must scale seamlessly. Without operational maturity, demand outpaces execution, and trust erodes quickly. This is critical for aggregator-led platforms, where retail media solutions built for restaurant aggregators must scale monetisation without slowing transactions.

d) A Deliberate On-Site and Off-Site Mix

On-site drives margin. Off-site drives growth. High-performing marketplaces design media programs that do both, and communicate clearly to sellers why each format exists and how value is measured.

e) Relentless Focus on Shopper UX

Every ad experience competes with conversion. Ads must be relevant, context-aware, and fast. If retail media degrades the shopping journey, the marketplace loses twice, in GMV and in advertiser confidence.

5. Conclusion: Retail Media ROI Is Bigger Than Ad Revenue

For marketplaces, the ROI of retail media operates on two levels. First, it’s a profit engine delivering high-margin revenue from owned attention through a scalable retail media network. Second, it’s a growth engine driving incremental traffic, higher conversion rates, and expanded GMV through on-site and off-site activation. 

Platforms that treat retail media as a scalable business, not a bolt-on feature, increasingly turn to modern retail media infrastructure, with Osmos playing a growing role in balancing monetisation and shopper experience.

When executed well, marketplaces aren’t just selling ad space. They’re selling outcomes: discovery, conversion, and growth. That outcome-led mindset attracts seller investment, strengthens platform economics, and positions retail media as a core business pillar and not a side initiative…

If you’re evaluating how retail media fits into your marketplace economics, book a demo to see how scalable attribution, yield control, and measurement actually come together.