Retail media networks (RMNs) are no longer a side bet. They are the ad business a retailer runs on top of its own store, selling two assets it already owns: high-intent shopper attention and transaction history. That combination lets brands place ads on retailer search results, category pages, apps, in-store screens and offsite inventory bought with the retailer’s customer data.
For performance marketers, the appeal is obvious. Retailers sit next to the point of purchase and can match ad exposure to actual sales, not proxies.
How Retail Media Networks Work
IAB Europe’s March 2025 pan-European definitions split retail media into three environments. Onsite covers the retailer’s own website and app. Offsite covers inventory the retailer does not own but targets with its audience segments. In-store covers screens, audio, connected shopping devices and printed materials inside physical shops.
Sponsored product listings remain the revenue core. Buyers bid on a cost-per-click basis inside the retailer’s auction, and the creative is assembled from the retailer’s product feed. Offsite buying works differently: loyalty and transaction segments are pushed into demand-side platforms, and the retailer matches exposure logs to purchase records afterwards, usually inside a clean room. That match creates closed-loop attribution, where the retailer can report sales rather than proxies.
Why This Is Reshaping Media Plans
The scale is impossible to ignore. Amazon reported $17.2 billion in advertising revenue in the first quarter of 2026, up 24%, and $19.8 billion in the second quarter, up 26%. Walmart closed fiscal 2026 with $6.4 billion in global advertising revenue, up 46%, with Walmart Connect growing 41%. European retail media grew 22.1% in 2024, far ahead of the 6.1% total advertising market.
But budgets matter as much as size. Retail media has historically been funded from trade and shopper marketing money negotiated alongside supplier terms. That is why endemic advertisers dominate, and why accounting treatment can change reported figures on both sides of the negotiation.
The Measurement Trap Marketers Should Watch
The biggest unresolved issue is that each network often marks its own homework. Research from Incremental in June 2026, based on more than 150,000 campaigns and $350 million in spend, found siloed attribution missed between 36% and 53% of total retail media impact. For offsite video, the missed share was between 67% and 80%, because a shopper exposed at one retailer often buys at another.
Compliance also lags the guidelines. Most retail media organisations do not yet factor viewability into attribution, and networks are slow to adopt certification. That means buyers are scaling budgets into a channel where measurement is still inconsistent.
What Growth Teams Should Do
- Separate onsite, offsite and in-store. They are different environments, priced and measured separately, not one product.
- Ask for attribution windows and extrapolation rates before launch. The IAB and MRC guidelines say lookback windows commonly run 3, 7, 14, 28 or 30 days and must be disclosed.
- Test incrementality. Closed-loop attribution inside one retailer’s ecosystem misses cross-retailer halo effects, which can be huge for offsite video.
- Use independent buying tools. Bid-management platforms and general DSPs are opening access, but each network still has its own console, taxonomy and reporting logic.
- Negotiate measurement as part of the deal. Certification and standards adoption should be a buying criterion, not an afterthought.
Retail media is genuinely different from a classic ad network: it starts from inventory and first-party data the operator owns. That is also why the measurement risk is concentrated in one place. The marketers who treat retail media as a data partnership, not just another ad buy, will get the most from it.
Source: PPC Land
