IAB retail media standards formalize endemic and non-endemic ad definitions

The formalization of these categories creates a technical gate for how streaming and commerce platforms monetize first-party data. For the ecosystem, this distinction separates high-margin endemic trade budgets from the broader brand budgets that networks like Amazon and Walmart need to sustain growth. As retailers like Walmart leverage hardware acquisitions to scale non-endemic reach, the technical enforcement of these standards ensures that shopper utility is not sacrificed for ad volume. Watch for whether non-endemic buyers accept modeled outcomes as a substitute for the closed-loop transaction data available to endemic brands.

The IAB's move to codify endemic and non-endemic definitions arrives as retail media networks race to standardize their technical infrastructure. In March 2025, the IAB Tech Lab released updated OpenRTB extensions specifically designed for retail media measurement, adding fields that allow demand-side platforms to distinguish between on-site and off-site retail inventory during programmatic transactions. Amazon Ads and Walmart Connect, the two largest retail media networks by revenue in the United States, have both adopted variations of these protocols to manage advertiser eligibility at scale. The IAB's broader retail media initiative has also published measurement guidelines that require networks to report endemic and non-endemic performance using consistent attribution windows, a step that directly affects how streaming commerce platforms like Amazon's ad-supported Prime Video tier allocate ad slots between trade and brand budgets.

On the business side, non-endemic spending is the growth engine that retail media networks depend on to justify their valuations. Amazon Ads reported retail media revenue exceeding $56 billion in 2024, with non-endemic categories such as financial services, automotive, and travel representing an increasing share of that total. Walmart Connect has pursued a parallel strategy: the company acquired Vizio in late 2024 for $2.3 billion specifically to extend its retail media reach into connected TV, creating a non-endemic-friendly inventory pool that spans linear and streaming. Criteo, which operates as an independent retail media enabler, has positioned its platform to help mid-tier retailers attract non-endemic buyers by offering closed-loop attribution that mirrors what endemic brands receive. DeepIntent has similarly built retail media integrations into its demand-side platform, allowing health and wellness advertisers to activate first-party shopper data across multiple networks simultaneously.

Technically, the OpenRTB extensions for retail media introduce new bid request fields that flag whether an impression originates from an endemic or non-endemic advertiser, enabling supply-side platforms to apply different pricing floors and frequency caps. The IAB Tech Lab's 2025 Retail Media Measurement Guidelines specify that endemic campaigns must report sales lift within a 14-day attribution window, while non-endemic campaigns may use modeled conversion estimates with a 30-day lookback. This asymmetry reflects the practical reality that endemic brands have direct access to transaction data on the retailer's platform, whereas non-endemic advertisers often rely on probabilistic matching. The standardization effort also intersects with broader industry moves toward clean rooms: the IAB Tech Lab published its Clean Room Standards in early 2025, establishing interoperability requirements that complement the endemic classification framework by defining how first-party data can be activated without exposing raw customer records to non-endemic partners.