CPG · Answer

Are retail media sales numbers independently audited?

No, and not at any network. Four of the six largest US retail media networks — Amazon, Walmart Connect, Criteo and Instacart — hold Media Rating Council accreditation, and every one of those accreditations covers delivery only: impressions, clicks, CTR, viewability, invalid-traffic filtration. Attributed sales, ROAS and incrementality are accredited nowhere. One network has put them into audit: Kroger submitted attributed sales, incremental sales, aROAS and iROAS for MRC pre-audit, in process since June 2026. Nothing has been granted. Treat every sales figure in a retail media report as a seller-produced number until an accreditation letter says otherwise.

The evidence

Accreditation stops at delivery, everywhere.

Amazon's accreditation covers Sponsored Products clicks and DSP impressions, clicks and viewability. Walmart Connect's covers Sponsored Search impressions, clicks and CTR. Criteo's covers onsite display rendered impressions and clicks. Instacart's covers impressions, clicks, CTR and viewable impressions. None names a sales metric. Roundel and Albertsons Media Collective are not listed in the MRC digital directory at all.

The one network in audit on outcomes is not one of the leaders.

Kroger's pre-audit scope is attributed sales, incremental sales, aROAS and iROAS across targeted onsite ads, product listing ads, onsite video and promoted carousels. It is the first outcome metric in the MRC's retail media pipeline. Amazon and Walmart, which take roughly 88% of US retail media spend between them, have submitted none.

The numbers are not comparable across networks either.

Attribution models, lookback windows and sales-scope definitions differ enough that the same campaign produces different figures at different networks. Criteo's post-click window is configurable at 7, 14 or 30 days. Walmart's public documentation says 14 days with 3- and 30-day options. Roundel's windows are not publicly documented at all. A cross-network ROAS comparison is comparing methodologies, not performance.

Incrementality is not the fix, on the networks' own evidence.

Albertsons Media Collective published research in March 2026 finding that iROAS can vary 6.5x, and flips the result in 83% of campaigns, depending on filtering, matching and revenue-calculation choices — choices the network makes. That is a company that sells incrementality reporting saying its own headline metric moves 6.5x on decisions the buyer cannot see.

What would have to be true for this to be wrong

If your networks can each produce a methodology document, a stated lookback window and a control-group definition on request, and those three line up closely enough that you can put their numbers in one table, then the comparability problem is yours to solve rather than theirs. Ask all of them in the same week and see how many answer. The ones that cannot are not hiding a number; they do not have a documented one.

MRC digital accreditation directory and services-under-review listing, checked September 2026. Network capability and window documentation from each network's own materials. Albertsons iROAS variance research, March 2026, published by Albertsons Media Collective. Share figures eMarketer, January 2026. Desk review, 22 sources, no instrument run.
Every row behind this answer is published in the standing study at cultmath.com/research/marketing/open-loop-retail-media, which is re-run on a schedule and corrected in place, dated.
Published 2026-11-09 by Ipalibo Da-Wariboko, CULT+MATH LLC. Where a number could not be sourced, this page says so and gives none.

This is one of six decisions covered in the cpg decision brief — each with the evidence behind it, who owns it, who it is contested with, and what would have to be true for the answer to flip.

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