Quick answer:
A retail media network (RMN) is an advertising platform a retailer builds on its own shopper data, selling brands ad placements on its website, its app, its in-store screens or partner channels. Amazon Ads, Walmart Connect and Target’s Roundel are the best-known examples.
The appeal is margin. Selling an ad impression costs a retailer almost nothing once the traffic and the data already exist, so retail media revenue carries a far higher margin than selling merchandise does. For a small retailer, the realistic role in all of this is as an advertiser on someone else’s network, not as the owner of one.
Retail media is the reason your supermarket now runs an ad sales team and the reason your supplier’s marketing budget increasingly gets spent inside a retailer’s app instead of on television.
Here is what a retail media network actually is, why the margin story has pulled every large retailer into it, how big the category is according to two forecasters who disagree, and what a six-store chain should realistically do about it.
What is a Retail Media Network? The Basics
You already own two things advertisers want: an audience ready to buy, and a record of what that audience actually bought. A retail media network turns both into inventory that brands can pay for.
The most common format is the sponsored product listing, where a brand pays to appear at the top of a search result inside your own site or app. Display banners, category takeovers and in-store screens fill out the rest.
What separates retail media from ordinary display advertising is measurement. Because you hold the transaction data, you can connect an ad impression to a purchase that followed it, which is usually called closed-loop measurement.
One caution on that: methodology varies by network, so what one platform counts as an ad-driven sale is not necessarily what another counts. Comparing reported return on ad spend across two networks is less straightforward than the dashboards make it look.
Why Retailers Build Them: The Margin Story
Start with the number that explains the entire category. On-site retail media inventory is commonly cited at roughly 70% to 90% gross margin, against grocery operating margins that often run 2% to 4%.
Treat that comparison as a widely repeated industry estimate rather than an audited figure. It traces to BCG-sourced commentary republished across trade press, and it was not verified here against a primary report, so the confidence on it is medium. The order of magnitude is the point, not the decimal place.
Off-site inventory is a weaker version of the same trade, running a lower 20% to 40% margin, because you are buying third-party ad space rather than selling your own.
Walmart’s reported results show what that gap does to a profit and loss. Walmart Connect took $6.4 billion in global advertising revenue in fiscal 2026, which is less than 1% of total company revenue. Yet advertising and membership income together came to roughly one third of Walmart’s operating profit in the fourth quarter of fiscal 2026, per the company’s own fiscal-year disclosures.
Under 1% of the revenue, about a third of the profit. That asymmetry is why every large retailer with traffic worth selling has built one of these, and why the money is worth chasing even when the ad business will never rival the store business in size.
There is a second reason retailers like the revenue: it is funded by supplier and brand marketing budgets. Unlike a markdown, it does not come out of the shopper’s wallet and it does not erode merchandise margin to get it.
The Three Placement Types
| Type | Where the ad runs | What it looks like |
|---|---|---|
| On-site | The retailer’s own site or app | Sponsored search results, product page banners, category placements |
| Off-site | External platforms | Social, display or connected TV ads targeted using the retailer’s shopper data |
| In-store | The physical store | Digital shelf screens, kiosks, endcap displays, in-store audio |
On-site is where the money is. The shopper is already inside a buying session, you own the surface, and the sale can be attributed cleanly.
Off-site extends your audience beyond your own properties. A grocer can take its purchase data and use it to target the same households on a streaming service, then match exposure back to till receipts.
In-store is the slowest of the three to scale, for an unglamorous reason: it needs hardware installed, powered and maintained in every location. Screens, network, mounting, service calls. That capital cost is why in-store retail media lags the other two even at retailers with heavy foot traffic.
Retail media is the paid layer, and it is worth keeping distinct from the digital shelf, which is the unpaid one. Titles, images, reviews and organic search ranking are the digital shelf, and they still need to be right, as any guide to optimizing product listings for retail SEO will confirm. Paid placement on top of a bad listing wastes the placement.
Who the Major Networks Are
eMarketer’s estimates of the 2025 US retail media ad market show a category with one dominant player and a long tail.
| Network | Estimated 2025 US share |
|---|---|
| Amazon Ads | 79.7% |
| Walmart Connect | 8.0% |
| Target Roundel | 1.5% |
Those three account for close to 90% of the market between them, on eMarketer’s numbers, and Amazon and Walmart alone are projected to take 89% of the incremental US retail media growth in 2026.
Everything else, and there are dozens of networks now including Kroger, Instacart, Best Buy and most large grocers, divides what is left.
The concentration matters for two practical reasons. As a buyer, you can reach most of the addressable audience through a small number of self-serve platforms. As a would-be builder, you would be entering a market where the top three networks already hold the budgets and set the measurement expectations.
For a small advertiser, that concentration is mostly good news. Amazon Ads and Instacart Ads both run self-serve campaign tools rather than agency-only sales channels, so testing a budget does not require a media buyer or a long contract.
The flip side is that performance benchmarks circulate mainly for the largest networks. A smaller network’s reported returns are harder to sanity-check against anything, which is a reason to run your own before-and-after read rather than accepting a platform’s number at face value.
How Big Is Retail Media?
Two forecasts get quoted constantly, and they are not measuring the same thing.
- eMarketer’s December 2025 forecast, referenced in its January 2026 published guidance, puts US retail media ad spending at $71.09 billion in 2026, up from $60.32 billion in 2025, growth of about 17.8%.
- WARC Media, in a report published August 19, 2026, puts global retail media ad spend at $200.4 billion in 2026 and $223.4 billion in 2027, reaching 15.2% of total global ad investment by 2027.
One is a US figure from eMarketer, the other a global figure from WARC Media. Different scopes, different methodologies, different firms, and they should never be blended into a single number. Any page quoting one total without naming a forecaster and a date is asking to be believed rather than checked.
WARC’s report also flags growth slowing. Excluding Amazon, it projects 9.8% growth for 2027, the lowest rate WARC has recorded for the category. The money is still arriving, just not at the rate the early years set as an expectation.
WORKED EXAMPLE: What This Means for a Small Retailer
A six-store regional hardware chain reads the margin story above and asks the obvious question: should it build a retail media network?
No. It has neither the traffic volume nor the first-party data depth to sell ad inventory that a brand would pay a worthwhile rate for. What it does have is a private-label line of grilling tools and a summer season to sell them in.
So it goes the other way and becomes a buyer. The chain sets a $3,000 monthly sponsored-placement budget, split across Instacart Ads and its wholesale distributor’s retail media program.
- Spend: $3,000 per month across two self-serve platforms.
- Delivered: 45,000 impressions on the sponsored placements.
- Attributed sales: $9,600 in incremental sales of the private-label tools.
- Return on ad spend: $9,600 divided by $3,000, or 3.2x.
The useful part is not the multiple. It is that the platform reports sales attributed directly to ad exposure, so the chain reads a number instead of estimating one from a marketing mix model it cannot afford to run.
Before trusting that 3.2x, the chain should ask what the platform counts as a conversion, over what attribution window, and whether the sale would likely have happened anyway. Closed-loop does not mean incrementality-proof.
The realistic position for a retailer this size is buyer, not builder. Building would require shopper traffic and data volume at a scale that makes inventory attractive to outside brands, plus ad sales, ad operations and measurement people to service it. No verified benchmark exists for the exact size at which that flips, which is itself a sign that nobody should be selling you a threshold. Reading up on how retail stores actually make money is a better use of an afternoon than a build-versus-buy spreadsheet at six stores.
Retail Media and Your Own Store Data
The asset underneath every retail media network is first-party data: what your customers bought, when, how often, and alongside what. Scale is what a small retailer lacks, not the data itself, since a six-store chain with a loyalty program collects the same kind of record a national grocer does.
Even at six stores, that data has uses that do not require selling a single ad. A customer data platform (CDP) unifies purchase records across your POS, your online store and your loyalty program into one profile per shopper. AI personalization then acts on those profiles in your own email and app messaging.
Clean, unified purchase data is also what makes campaign targeting work when you buy placements on someone else’s network, and the direction of travel in AI and ecommerce advertising keeps raising the value of having it in order. The data is worth organizing whether or not there is ever an ad business attached to it.
Related Terms
- The Digital Shelf: the unpaid listing layer retail media sits on top of.
- Customer Data Platform (CDP): where shopper data gets unified.
- AI Personalization: acting on that data in your own channels.
- Dynamic Pricing: the other use for live shopper signals.
