A retail media network is the advertising business a retailer operates on top of its own shop. It sells brands two assets the retailer already owns: the attention of people who arrive with an intention to buy, and the record of what those people have purchased before. Advertising runs on the retailer's search results, category and product pages, its app, screens inside its stores, and on third-party inventory bought using its customer data. The abbreviation RMN is common in trade documents and sales decks.

The category exists for a commercial reason rather than a technical one. Grocery and general merchandise operate on thin margins, while selling advertising against traffic already paid for carries almost none of the cost of goods. The IAB and the Media Rating Council, in guidelines published in January 2024, frame retail media as marketing to shoppers near the point of purchase or the point of choice between brands, spanning both online and in-store advertising.

How a network is assembled

IAB Europe's pan-European definitions, published on March 26, 2025, split the inventory into three environments. Onsitecovers a retailer's owned website and app. Offsite covers inventory the retailer does not own but sells against with its audience segments. In-store covers screens, audio, connected shopping devices and printed materials inside the shop. Most networks sell all three, priced and measured separately.

Sponsored product listings remain the revenue core. These trade on cost per click inside the retailer's own auction, and the creative is assembled by the retailer from its product feed rather than supplied by the buyer. That single detail kept the format outside real-time bidding for a decade, because standard programmatic assumes the bidder arrives with a finished asset. IAB Tech Lab closed the gap on January 24, 2025, finalising an OpenRTB extension that introduces a prodfeed object inside the bid request, carrying the domain of the feed owner plus arrays of allowed and blocked products, with a matching Native Ads data type so a bidder can respond with a product identifier alone. Pentaleap and Teads ran the first real-time bidding integration for onsite sponsored products in July 2025.

Offsite works differently. Segments built from loyalty and transaction records are pushed into a demand-side platform, and the bid request carries no marker identifying the impression as retail media. What distinguishes it is the reconciliation afterwards, when exposure logs are matched against purchase records, usually inside a clean room.

That match is the product. Because the retailer controls both the ad server and the till, it can report sales rather than proxies, an arrangement the industry calls closed-loop attribution. The IAB and MRC guidelines note that lookback windows commonly run to 3, 7, 14, 28 or 30 days and must be disclosed before a campaign starts. They also require networks to state what proportion of attributed sales is extrapolated, since cash payments, missing loyalty scans and device privacy settings leave a share of buyers unidentified.

Few retailers build the machinery. Criteo, Epsilon Retail Media, Koddi, Topsort, Kevel, Pentaleap and Amazon's Retail Ad Service supply the ad serving; Amazon and Walmart are the main exceptions that built their own. On the buy side, brands work through retailer consoles, through bid-management tools such as Pacvue and Skai, and increasingly through general demand-side platforms.

Origin and evolution

Amazon began selling sponsored placements inside its own search results in 2012, and most industry accounts date the category from there. Criteo bought the retail search firm HookLogic in 2016, a move AdExchanger described as the acquisition of direct retailer data links rather than technology. Walmart relaunched its media business as Walmart Connect in 2021, adding in-store screens and data integrations. A long tail followed: signage vendor Broadsign counted more than 200 retail media networks operating worldwide as of 2025.

Standards arrived late and in sequence. The IAB and MRC opened their retail media measurement guidelines for comment on September 13, 2023 and published the final text in January 2024. IAB Europe issued its own measurement standards in April 2024, then joined the IAB to open in-store definitions for public comment on September 18, 2024, finalised that December. A certification programme using independent auditors launched in October 2024, with Albert Heijn the first network certified in September 2025. Guidelines for incremental measurement followed on November 3, 2025.

Supply of the underlying technology consolidated at the same time. Amazon opened its retail advertising stack to other retailers with Retail Ad Service on January 9, 2025, weeks after Microsoft shut down PromoteIQ.

Why it matters for marketers

The money is now large enough to reorder media plans. Amazon reported first-quarter 2026 advertising revenue of $17.2 billion at 24% growth, taking the trailing twelve-month total past $70 billion, then $19.8 billion in the second quarter at 26%. Walmart closed fiscal 2026 with $6.4 billion of global advertising revenue, up 46%, of which Walmart Connect grew 41% without the VIZIO acquisition it completed that year. European growth ran at 22.1% in 2024 against 6.1% for the advertising market as a whole.

Category forecasts disagree sharply. WARC Media put worldwide retail media investment at 200.4 billion dollars for 2026, rising to 223.4 billion in 2027, while research from NIQ and World Data Lab in August 2026 sized the current global market at 184 billion dollars and Omdia projected more than 300 billion by 2030. None of the three separates onsite, offsite and in-store on the same basis.

Where the budget comes from matters as much as its size. Retail media has historically been funded from trade and shopper marketing money negotiated alongside supplier terms, which is why endemic advertisers dominate. IAB Europe and Mediasense examined the consequences on March 12, 2026, showing how the choice between booking retail media as revenue or as a cost offset changes reported figures on both sides of the negotiation.

Fragmentation is the operational cost. The share of brands working with four to six networks doubled from 10% to 24% during 2025, each with its own console, taxonomy and attribution window.

Limitations and disputes

The central criticism is that each network marks its own homework. Research published by Incremental in June 2026, drawing on more than 150,000 campaigns and $350 million of spend, found siloed attribution missing between 36% and 53% of total retail media impact, and between 67% and 80% for offsite video, because a shopper exposed at one retailer often buys at another. The IAB and MRC guidelines concede the same boundary, stating that their incrementality chapter covers effects inside a retailer's own ecosystem rather than the halo beyond it.

Compliance lags the standards. The guidelines acknowledge that most retail media organisations do not yet factor viewability into attribution, despite MRC thresholds of 50% of pixels for one second on display and two seconds on video. Adoption data points the same way: IAB Australia research presented in July 2026 found 60% of buyers increasing investment while only 22% of networks called their own offering advanced, with 80% saying certification would make them likelier to partner. Agency satisfaction with networks had already fallen from 66% to 44% between surveys presented at the same body's 2025 summit, even as budgets rose.

A second dispute concerns whether the category is new money. Executives at Metcash argued in July 2026 that a narrowing focus on incremental sales risks shrinking the commercial ceiling of networks that recycle trade dollars rather than winning brand budgets.

The supplier economics are also under strain. Criteo's second-quarter 2026 results showed media spend through its platform rising 9% while contribution excluding traffic acquisition costs fell 12%, evidence that retailers are insourcing the media business and paying for technology alone.

Not the same as

A commerce media network is the wider category. It covers any operator monetising transaction data, including payments, travel and delivery businesses with no shop: Mastercard launched one in October 2025, quoting a 22 times return figure of its own making. IAB Europe treats retail media networks as a subset.

Onsite and offsite are environments inside a network, not alternatives to it. A single network normally sells both.

Shopper marketing and trade promotion describe the budget and the commercial negotiation, not the media. Retail media is frequently paid for from those funds without being the same thing.

An ad network in the classic sense aggregates third-party publisher inventory for resale. A retail media network starts from inventory and data the operator owns.

Recent developments

The walls are coming down on the data. Walmart Connect made shopper audiences available in Yahoo DSP on May 28, 2026, routed through Magnite and covering VIZIO connected television inventory, then extended the same audiences into Display & Video 360 for YouTube in June. The Trade Desk had already opened onsite inventory to its buyers through Koddi in October 2025.

Measurement is moving in the same direction. Amazon began naming the specific outside retailers where its ad exposure converts through retailer-level Omnichannel Metrics on July 7, 2026. The newest surface is conversational: Amazon advertisers gained access to a ChatGPT Ads pilot on September 10, 2026.

Timeline

  • 2012: Amazon begins selling sponsored placements inside its own search results
  • 2016: Criteo acquires HookLogic, adding direct retailer data relationships
  • 2021: Walmart relaunches its media business as Walmart Connect
  • September 13, 2023: IAB and MRC open retail media measurement guidelines for public comment
  • January 2024: IAB and MRC publish the final Retail Media Measurement Guidelines
  • April 2024: IAB Europe publishes Retail Media Measurement Standards V1
  • September 18, 2024: IAB and IAB Europe open in-store definitions and standards for comment
  • October 2024: IAB Europe launches its retail media certification programme
  • December 3, 2024: the joint in-store definitions and measurement standards are finalised
  • January 9, 2025: Amazon announces Retail Ad Service; Microsoft closes PromoteIQ
  • January 24, 2025: IAB Tech Lab finalises the OpenRTB product listing ad extension
  • March 26, 2025: IAB Europe publishes harmonised onsite, offsite and in-store definitions
  • July 24, 2025: Pentaleap and Teads announce real-time bidding for onsite sponsored products
  • September 2025: Albert Heijn becomes the first IAB Europe certified retail media network
  • November 3, 2025: IAB and IAB Europe publish incremental measurement guidelines
  • June 2026: Incremental quantifies the cross-retailer halo missed by siloed attribution
  • July 7, 2026: Amazon adds retailer-level breakouts to Omnichannel Metrics
  • August 2026: NIQ and World Data Lab size the global retail media market at 184 billion dollars

Summary

Who: Retailers and marketplaces operating the media business, endemic brands and their shopper marketing and media teams buying it, and a technology layer including Criteo, Epsilon Retail Media, Koddi, Topsort, Pentaleap, Kevel and Amazon Retail Ad Service. Standards come from the IAB, IAB Europe, IAB Tech Lab and the Media Rating Council.

What: An advertising business run by a retailer across its own site and app, its physical stores, and third-party inventory bought with its shopper data, sold on the strength of purchase records that let exposure be matched to transactions.

When: Commercially established from Amazon's sponsored placements in 2012, scaled by Walmart Connect from 2021, defined by the IAB and MRC in January 2024 and by IAB Europe through 2024 and 2025, and opened to programmatic buying from the OpenRTB product listing ad extension of January 24, 2025 onward.

Where: Retailer search results, category and product pages, apps, in-store screens and audio, and offsite display, video and connected television inventory bought through demand-side platforms.

Why: Retailers hold first-party purchase data that advertising platforms cannot replicate, and advertising carries margins that retail trading does not. The unresolved question is measurement: networks report on their own performance, siloed attribution misses a third to a half of documented impact, and buyers continue to increase budgets faster than networks adopt the standards written to make them comparable.