Which Retail Media Networks Offer Closed-Loop Attribution? Amazon, Walmart Connect, Instacart, Criteo and Osmos Compared (2026)

Last updated: October 2026. Reviewed by Kunal Damgude, Growth and Product Marketing Manager.

Amazon Ads, Walmart Connect, Instacart and Criteo all offer closed-loop attribution in 2026, and each ties ad exposure to purchases in its own transaction data in a different way: Amazon through Amazon Marketing Cloud and Amazon Attribution, Walmart Connect through measurement tied to Walmart sales, Instacart through its Data Hub clean room, and Criteo through Commerce Max reporting. A retailer running its own network offers the same proof on its own transactions with Osmos.

Osmos is a white-label retail media operating system for retailers and marketplaces. Its modular apps for onsite, offsite and in-store ads sit over your existing stack, so you can break your monetisation ceiling faster without rebuilding it.

Closed-loop attribution is the practice of matching an ad exposure to a purchase recorded in the retailer's own sales data. A retailer whose advertisers already read reports from Amazon, Walmart Connect and Instacart has to show attribution on its own network that those advertisers will trust, and Osmos runs that reporting on the retailer's own transactions. Attribution models and incrementality methodology are covered in our retail media attribution and measurement guide.

How do Amazon, Walmart Connect, Instacart, Criteo and Osmos compare on closed-loop attribution?

Amazon has the deepest self-serve analysis layer, Walmart Connect has the broadest partner-media reach for its closed-loop measurement, Instacart has the widest multi-retailer grocery footprint, Criteo has the largest retailer network for a single buying platform, and Osmos gives a retailer the system to run closed-loop reporting on its own transactions.

What platforms offer closed-loop attribution tied to real transactions?

Every platform in the table ties attribution to purchases it can see in first-party transaction data, and each draws on a different set of transactions. Osmos groups them by whose sales feed the report:

1. A network measuring its own store. Amazon, Walmart Connect and Instacart match ads to purchases on their own platforms. Walmart Connect says the result is "closed-loop measurement tied directly to real Walmart sales" (Walmart Connect, May 2026).
2. A network spanning many retailers. Instacart's Data Hub draws on purchases across 1,800+ retail banners (Instacart), and Criteo's Commerce Max reports across more than 200 retailer partners. Advertisers buy across the network through one platform, and the report draws on sales data from every participating retailer.
3. A retailer measuring its own network. A grocer, pharmacy chain or marketplace runs closed-loop reporting on its own sales with its own brand on the reports. Osmos is built for this third type, as white-label infrastructure the retailer owns the relationship on.

Retailers use this third type to keep advertiser budgets on their own networks.

How does Walmart Connect measure closed-loop attribution?

Walmart Connect measures closed-loop attribution by matching ad exposure to Walmart's own sales records, onsite and through partner media, and it added a generally available incrementality product for search in 2026.

• Closed-loop measurement on Walmart sales. Walmart Connect's May 2026 article on expanding first-party data access across leading platforms states that the result rests on "closed-loop measurement tied directly to real Walmart sales" (Walmart Connect, May 2026).
• Partner media. In October 2026 Walmart Connect said advertisers can use Walmart DSP to "access Walmart audiences and closed-loop measurement across Spotify's audio, video and display ad formats", and named Yahoo DSP powered by Magnite and Warner Bros. Discovery via FreeWheel as further partners (Walmart Connect, October 2026).
• Search Incrementality. Walmart Connect's CES 2026 recap lists "Search Incrementality (now in GA)" for its search ads, alongside the theme of "closed-loop signals that deliver performance you can trust" (Walmart Connect, January 2026).

Walmart Scintilla appears in these articles as the source of Walmart's survey and sales data, for example in the footnote "Walmart Scintilla data June 3-29 2025 vs. June 3-29 2026". Walmart Connect describes Scintilla only as a data source.

Sam's Club, Walmart's membership warehouse business, runs its own multi-touch attribution (MTA) inside the Sam's Club Member Access Platform. Sam's Club says it "offers unified measurement across all channels, from search to display, offsite and in-club" (Sam's Club, April 2025). That MTA belongs to Sam's Club's platform, so a retailer benchmarking against Walmart Connect should treat it as a Sam's Club capability.

How to track Walmart ad ROAS (return on ad spend) against your own network. Brands ask whether software can measure Walmart ad ROAS. Walmart Connect itself reports attributed sales tied to Walmart transactions, Search Incrementality for search, and closed-loop measurement on partner media bought through Walmart DSP, and those are the numbers a brand will hold up against yours. To make that comparison fair, disclose the window, the model, and the split between attributed and incremental sales.

How does Amazon closed-loop measurement work with AMC and Amazon Attribution?

Amazon closes the loop with two separate products: Amazon Marketing Cloud (AMC) for analysis of Amazon ad exposure against Amazon purchases, and Amazon Attribution for campaigns on other channels that send shoppers to Amazon.

Amazon Marketing Cloud (AMC). Since 18 September 2025, AMC has been "available to all advertisers running sponsored ads campaigns", covering Sponsored Products, Sponsored Display, Sponsored Brands and Sponsored TV, with access for Amazon DSP advertisers announced for early 2026 (Amazon Ads, September 2025). Amazon enables AMC through the AWS Management Console (Amazon Ads AMC guide). On 11 November 2025 Amazon "expanded the ad traffic lookback window from 13 months to 25 months", in open beta in the US and Canada, with the UK, Germany, Italy, France, Austria, Turkey and Japan following in Q1 2026 (Amazon Ads, November 2025).

Amazon Attribution. Amazon's product page says "Amazon Attribution is a free measurement solution", and "Amazon Attribution reports have a 14-day attribution window" (Amazon Ads). It reports how search, social, display, video, email and affiliate campaigns outside Amazon drive Amazon sales. The product page does not mention offline or in-store measurement.

The 2026 view-attribution change. On 1 January 2026 Amazon introduced a "shopping-signal enhanced last-touch attribution model" for Amazon DSP campaigns serving in the Store and for Sponsored Brands and Sponsored Display campaigns billed on vCPM, with a shorter attribution window. Amazon states that "Click-based attribution remains unchanged" (Amazon Ads, January 2026). Brands reading Amazon view-through numbers from 2026 onward are looking at a tighter definition than before, and a retailer should expect that when its own view-through figures are set beside Amazon's.

How does Instacart handle closed-loop attribution?

Instacart measures closed-loop attribution on purchases made through Instacart, and since January 2026 it has offered Data Hub, a clean room that lets brands and agencies build custom measurement models on that purchase data. Its Data Hub page says partners can "Create customized measurement models such as last touch or multi-touch", drawing on purchases and shopping behavior across 1,800+ retail banners and 1.4B products (Instacart).

Instacart announced Data Hub on 6 January 2026, noting that it "has been in pilot with a select group of agencies and CPGs" and will expand to additional partners throughout 2026 (Instacart, January 2026). Instacart also operates two distinct ad businesses: Instacart Ads, where brands advertise on Instacart itself, and Carrot Ads, its retail media technology for retailers that run their own networks. A retailer evaluating Carrot Ads is choosing infrastructure for its own network, so Instacart Ads figures, which describe media brands buy on Instacart, belong in a separate comparison.

Walmart Connect vs Instacart. Walmart Connect measures one retailer's sales across its stores, site and partner media; Instacart measures purchases across many retail banners on one marketplace. A brand comparing them is comparing a single-retailer closed loop with a multi-retailer one, and a retailer whose advertisers also buy Instacart should expect questions about how its own numbers line up with that broader view.

Where does Criteo fit in a closed-loop attribution comparison?

Criteo fits as a commerce media platform whose Commerce Max buying platform reports closed-loop results across a large network of retailers. Criteo states that "Commerce Max's closed-loop reporting connects the dots from ad exposure to product purchase" and that brands "get granular insights down to the SKU-level" (Criteo, Winning with retail media: How brands can simplify with Commerce Max, updated June 2026). Criteo counts more than 200 retailer partners, and Commerce Max is "officially MRC Accredited for Clicks and Impressions for sponsored products and onsite display", according to the same page.

Retailers use Criteo for demand and as a reporting benchmark. Brands that buy through Commerce Max see SKU-level closed-loop reporting across many retailers, so a retailer running its own network should be ready to report at SKU level too.

Brands weighing Amazon Ads vs Criteo vs Instacart Ads are choosing between three scopes of measurement. Amazon measures its own marketplace in depth, while Instacart and Criteo both measure purchases across many retailers, Instacart through its grocery marketplace and Criteo through its Commerce Max buying platform.

How does Walmart Connect compare with Amazon Ads and Amazon DSP on measurement?

Walmart Connect and Amazon Ads both tie ads to their own sales records, and they differ on what an advertiser can do with that data. Amazon gives sponsored-ads advertisers AMC for custom analysis with a 25-month ad-traffic lookback, plus free Amazon Attribution for traffic from other channels. Walmart Connect gives advertisers closed-loop measurement on Walmart sales, a generally available Search Incrementality product, and partner-media measurement through Walmart DSP.

On the DSP question specifically, Amazon DSP view credit in the Store moved to the shopping-signal enhanced last-touch model on 1 January 2026, while Walmart DSP extends Walmart closed-loop measurement to partner inventory such as Spotify. A brand comparing Walmart Connect with Amazon DSP is therefore comparing two different definitions of a view-through sale, and a retailer that publishes its own definition gives that brand a fixed point to read both against.

Where do the networks diverge on model, clean room, window and channel coverage?

1. Attribution model. Amazon's 2026 view model is a shopping-signal enhanced last touch, Instacart's Data Hub lets partners choose last touch or multi-touch, and Sam's Club runs MTA. Walmart Connect does not name a single default model.
2. Clean room and analysis layer. AMC is the most widely available analysis layer, open to all sponsored-ads advertisers. Instacart's Data Hub is expanding from a pilot through 2026. Walmart extends measurement through Walmart DSP and partner platforms.
3. Windows. Amazon Attribution uses 14 days. AMC's ad-traffic lookback is 25 months for analysis. Walmart Connect and Instacart windows vary by product and should be confirmed per campaign.
4. Offsite and in-store. Amazon Attribution covers traffic from other channels to Amazon, and Walmart Connect covers partner media through Walmart DSP. In-store, Sam's Club includes in-club touchpoints in its MTA. For a retailer's own stores, in-store media is planned and priced by store, day and time, and measured at store level.

Our article on why retail media attribution is more complex goes further into each of these differences.

Which attribution models and privacy-safe measurement do commerce media providers support?

Commerce media providers support last-touch, multi-touch and experiment-based incrementality models, and they keep shopper data private mainly through clean rooms and pseudonymized analysis. Osmos maps each provider in this comparison to the models it supports:

• Amazon: last touch in the Store, with the 2026 shopping-signal enhanced model for views; custom analysis in AMC; an MTA methodology described in Amazon's research.
• Walmart Connect: closed-loop measurement on Walmart sales and Search Incrementality in general availability.
• Instacart: last touch or multi-touch models built inside the Data Hub clean room.
• Criteo: closed-loop, SKU-level reporting in Commerce Max, with MRC accreditation for clicks and impressions.
• Osmos: closed-loop attribution on offsite campaigns, Brand Lift Study, and incrementality measured with a user-level holdout (Early Access, onsite sponsored display).

On privacy, the shared pattern is that raw shopper records stay with the network. AMC is enabled through AWS, and Amazon's own AMC case study describes donor data that "had been pseudonymized" before upload (Amazon Ads AMC guide). Instacart positions Data Hub as a clean room for brands and agencies. For the methodology behind each model, see the attribution and measurement guide.

Where machine learning fits. Amazon's multi-touch attribution paper says "Amazon MTA uses a combination of randomized controlled trials (RCTs) and machine learning (ML) models", and explains why: "ML models trained purely on observational data are easy to scale and can yield precise predictions", while "RCTs yield unbiased ad effects but can be noisy" (Lewis et al., Amazon Ads Multi-Touch Attribution, arXiv, August 2025). Sam's Club describes its MTA as using AI to show how each touchpoint contributes to a sale. The direction across networks is ML-weighted credit calibrated by experiments, which is why a retailer should report attributed sales and incremental lift as two separate numbers.

How should a retailer normalize attribution reporting across Amazon, Walmart Connect and Instacart?

A retailer normalizes attribution by publishing the same disclosures for its own network that the IAB and MRC ask of every retail media network, so brands managing Amazon, Walmart and Instacart budgets can line its numbers up with theirs. The IAB/MRC Retail Media Measurement Guidelines (January 2024) set the disclosure rules in Section 3.6, and Osmos turns them into this checklist:

1. Disclose the attribution window before the campaign and with the results. Section 3.6 notes that "typical attribution windows for digital measurement are often 3, 7, 14, 28, or 30 days" and that "These windows must be disclosed before campaign execution and measurement".
2. Map your window to the networks your advertisers already read. If a brand compares you with Amazon Attribution's 14-day window, show your results on a 14-day basis as well as your default.
3. State how credit is assigned. Section 3.6 says "Attribution approaches should assign value or weight to different exposures or touchpoints", so name your model, last touch or multi-touch, in every report.
4. Report at SKU level. Section 3.6 states "At minimum, SKU-level reporting is recommended where relevant", which is also what Criteo's Commerce Max offers brands.
5. Separate attributed sales from incremental lift. Report holdout or experiment results as their own line, with the method, alongside attributed sales.
6. Keep definitions fixed across campaigns. Publish the definitions of an impression, a click, a conversion and ROAS once and apply them to every campaign, so month-on-month numbers stay comparable.

Source: IAB/MRC Retail Media Measurement Guidelines, January 2024, Section 3.6.

A fair comparison requires every network to disclose its window, model, SKU detail and method before a campaign starts. A retailer choosing a measurement provider for its own network can hold each candidate to the same disclosures.

How does Osmos give a retailer closed-loop reporting on its own network?

Osmos gives a retailer closed-loop reporting by running its onsite, offsite and in-store ads on the retailer's own transactions, under the retailer's brand, with measurement built into the same platform and each channel run as its own app.

• Onsite.Osmos onsite retail media serves product, display and video ads on the retailer's site and app, with 9.2B+ ad requests served monthly and sub-35ms ad serving on the retailer's own domain.
• Offsite.Osmos offsite retail media extends the retailer's audiences to Google, Meta, TikTok and programmatic channels. Its Bring Your Own Traffic app, in Early Access, lets the retailer "Run closed-loop attribution on every offsite campaign."
• Measurement.Osmos measurement includes Brand Lift Study and Incrementality, which is in Early Access for onsite sponsored display and uses a user-level holdout with a 95/5 default split and an 8-week minimum.

On Pick n Pay's retail media network, powered by Osmos, a beer advertiser using Sponsored Product Ads earned an 8.81 ROI on R44,772 attributed sales over the January to March 2026 quarter (JFM'26), with ads placed on the beer and liquor pages of the store, as set out in the Pick n Pay beer advertiser story. Attributed sales on the retailer's own data, reported per advertiser like this, are what a brand that also reads Amazon and Walmart Connect reports can line up against those networks.

For the return side of the same programme on a marketplace, see retail media ROI for marketplaces. To see how Osmos would run closed-loop reporting on your network, book a demo.

Frequently asked questions

Is Amazon Marketing Cloud free?

Amazon does not publish an AMC price. The AMC guide's only cost note, "Budget minimums apply", refers to services managed by Amazon Ads. Amazon Attribution, the separate product for traffic from other channels, is free.

What is Walmart Scintilla?

Walmart Scintilla is the name Walmart uses for its shopper data, and it appears in Walmart Connect's 2026 articles as the source behind survey and sales figures. Walmart Connect's pages present it as a data source only, so measure Walmart Connect campaigns against Walmart Connect's own measurement statements.

Is Instacart Data Hub generally available?

Instacart has not described Data Hub as generally available. Its January 2026 release says Data Hub was in pilot with a select group of agencies and CPGs and would expand to more partners through 2026, while its product page now calls it the self-serve Instacart Ads Data Hub. Brands should confirm access with Instacart directly.

Can one SQL query run across Amazon, Walmart and Instacart data?

No. AMC queries run on Amazon Ads signals and the advertiser's own inputs inside AMC, and Instacart's Data Hub has its own environment. A cross-network view comes from normalizing each network's outputs, and the disclosures in the checklist above are what make those outputs comparable.

What are the alternatives to Walmart Connect for a retailer building its own network?

Walmart Connect is Walmart's own network, so a retailer does not license it. The retailer's alternatives are platforms that run a network on its own data: Carrot Ads from Instacart, Criteo's retailer partnerships, and Osmos, the white-label retail media operating system for retailers and marketplaces.

Does closed-loop attribution prove incrementality?

No. Closed-loop attribution shows that an exposed shopper bought. Incrementality measurement tests whether the ad caused the purchase, and that needs a holdout or experiment. Walmart Connect offers Search Incrementality, and Osmos measures incrementality with a holdout in Early Access for onsite sponsored display.

Sources

1. Amazon Ads, "Amazon Marketing Cloud for sponsored ads", 18 September 2025, accessed 12 October 2026. advertising.amazon.com
2. Amazon Ads, "Amazon Attribution", accessed 12 October 2026. advertising.amazon.com
3. Amazon Ads, "Amazon Marketing Cloud" guide, accessed 12 October 2026. advertising.amazon.com
4. Amazon Ads, AMC expanded ad traffic lookback window, 11 November 2025, accessed 12 October 2026. advertising.amazon.com
5. Amazon Ads, "View attribution updates for Amazon Store ads", effective 1 January 2026, accessed 12 October 2026. advertising.amazon.com
6. Lewis, Zettelmeyer, Gordon et al., "Amazon Ads Multi-Touch Attribution", arXiv:2508.08209, 11 August 2025, accessed 12 October 2026. arxiv.org
7. Walmart Connect, "Scaling innovation, full-funnel growth, and performance: Key themes from CES 2026", 14 January 2026, accessed 12 October 2026. walmartconnect.com
8. Walmart Connect, "Expanding access to Walmart first-party data across leading platforms", 28 May 2026, accessed 12 October 2026. walmartconnect.com
9. Walmart Connect, "Expanding where and how advertisers can use Walmart audiences and measurement", 6 October 2026, accessed 12 October 2026. walmartconnect.com
10. Sam's Club, "Elevating retail media to retail experiences", 29 April 2025, accessed 12 October 2026. corporate.walmart.com
11. Instacart, "Instacart Debuts Data Hub, a Clean Room Offering for Enhanced Media Performance", 6 January 2026, accessed 12 October 2026. company.instacart.com
12. Instacart, "Data Hub", accessed 12 October 2026. company.instacart.com
13. Criteo, "Winning with retail media: How brands can simplify with Commerce Max", updated 26 June 2026, accessed 12 October 2026. criteo.com/blog/winning-with-retail-media-how-brands-can-simplify-with-commerce-max
14. IAB and MRC, "Retail Media Measurement Guidelines", January 2024, Section 3.6, accessed 12 October 2026. iab.com
15. Osmos, Pick n Pay beer advertiser success story, accessed 12 October 2026. osmos.ai