Amazon Ads says 20% of brand sales value lands after attribution closes

Amazon estimates that roughly a fifth of a brand's value generated by its ads arrives after the attribution window — typically seven to 30 days — has already closed. The company reached that figure by analyzing more than 2 million campaigns that ran across its ad products in June, and it is now using the findings to argue that advertisers should count value over a full year.

The claim comes with a caveat: it is Amazon's own estimate of its own ad products, based on its own campaign data. No independent verification of the 20% figure has been published. Still, the push toward longer measurement windows reflects real structural pressure on the retail giant's ad business.

Lily Tong, a director of measurement at Amazon Ads, framed the gap as a measurement cutoff problem rather than a performance problem. "What we actually find is that roughly 20% of the sales value for a brand shows up over time and isn't captured in that immediate attribution window because that's just a cutoff date for measurement," she said. "It doesn't mean that you didn't create value."

For practitioners, the implications cut in several directions. Media buyers running Amazon campaigns should expect the platform to market extended attribution windows more aggressively, since proving value over longer stretches is becoming table stakes — and Amazon, like Google, needs that proof more than most. Two forces are squeezing search budgets: better upper-funnel measurement and AI-driven shopping experiences are pulling money out of search, while TikTok, Instagram, YouTube and creators increasingly claim credit for sales they influenced even when the final purchase happens on Amazon.

That last point matters for anyone managing multi-channel budgets. If social platforms and creators can demonstrate they drove a sale — even one completed on Amazon — then Amazon's case for a year-long window is partly defensive. The retailer wants to capture credit it currently loses when a seven-to-30-day window expires, and brands will have to decide which platform's attribution math they trust when the same sale appears in multiple dashboards.

The practical risk for advertisers is inflated, double-counted conversions as every platform stretches its measurement horizon. The practical opportunity is a fuller picture of delayed purchase behavior that short windows have always truncated. Both outcomes depend on how rigorously Amazon's 20% estimate holds up under scrutiny, and so far the supporting methodology rests on a single month of campaign data.

Expect the measurement-window fight to intensify. As AI-mediated shopping and creator commerce keep blurring the line between discovery and purchase, Amazon's push to count a full year of ad-driven value signals where platform attribution is heading next.