Non-endemic advertising represents a significant growth opportunity for retail media networks (RMNs) as endemic brand advertising approaches saturation. This strategy allows retailers to monetize their first-party data by selling ad space to brands promoting products or services not sold by that retailer. With US retail media ad spend hitting $60.32 billion in 2025, retailers and advertisers alike are exploring how non-endemic partnerships can expand reach, unlock new revenue streams, and deliver relevant advertising experiences to shoppers.

What is non-endemic advertising in retail media?

Non-endemic advertising is a retail media strategy where retailers sell ad space to advertisers promoting products or services not sold by that retailer. It expands inventory beyond the retailer's own product catalog to complementary offerings.

"If I'm the Home Depot and I'm serving a barbecue sauce ad next to a grill product, that might be a non-endemic advertisement," EMARKETER analyst Sarah Marzano explained. This differs from endemic advertising, where brands promote products the retailer carries.

Non-endemic ads can appear on-site (retailer websites, apps, in-store placements) or off-site (using retailer data to target audiences across other websites and platforms). While Amazon and Walmart have incorporated non-endemic advertising for years, broader adoption is accelerating as RMNs seek new growth avenues.

Why are retail media networks pursuing non-endemic advertisers?

Retail media networks are pursuing non-endemic advertisers because endemic brand spending is approaching saturation. Amazon and Walmart will account for 88.2% of retail media digital ad spending in 2026, according to EMARKETER's December 2025 forecast, leaving dozens of remaining RMNs competing for a small slice of the pie.

"Retailers who have more mature, developed retail media networks are recognizing that they might be reaching a level of saturation among their endemic brands," Marzano said. "Even though they might be looking at growth from those programs over the next few years, it's not as significant of growth as they might like to see."

Non-endemic partnerships provide a new revenue stream, diversify the advertiser base, and allow retailers to monetize their valuable first-party data beyond their traditional product catalogs.

Which industries are spending the most on non-endemic retail media?

Financial services, travel, and media are leading non-endemic advertising adoption in retail media. US financial media network ad spend reached $640 million in 2025, growing 83.1% YoY. Travel media network ad spend hit $1.81 billion in 2025, a 12.2% increase.

Walmart Connect now offers offsite media to non-endemic brands in automotive, entertainment, financial services, quick-service restaurants, and travel. Home Depot is targeting financial services and telecom advertisers, betting its ability to segment audiences based on home improvement projects will attract these categories.

According to 58% of advertisers surveyed, they are interested in leveraging non-endemic data to target qualified audience segments.

How do non-endemic campaigns use retailer first-party data?

Non-endemic campaigns leverage retailer first-party data to create highly targeted, qualified audiences without relying on third-party cookies. Retailers possess purchase data, browsing behavior, and loyalty program information that reveals consumer preferences and intent.

"The value of retailers' first-party data has been more than proven by the success we've seen from retail media networks over the past decade," Marzano noted.

Data collaboration between networks enables cross-platform attribution. "Let's say you're in a car ride share app, and you ride to the grocery store. On the way, you saw an ad in the car share, and then when you get to the store, you buy the product," explained Jeffrey Bustos, senior vice president of retail media analytics at Merkle. "The data collaboration between both networks can provide that attribution."

What are the main challenges of non-endemic advertising for retailers?

Non-endemic advertising presents several challenges for retailers navigating this emerging opportunity:

• Maintaining relevance. Retailers must ensure non-endemic ads complement their core offerings without alienating shoppers. Contextual alignment matters: Luxury skincare brands paired with high-end fashion platforms work better than discount electronics outlets.
• Avoiding competition with endemic brands. Care must be taken to prevent non-endemic ads from directly competing with products the retailer sells.
• Measurement complexity. Tracking non-endemic campaign success is more challenging than traditional retail media, requiring new attribution approaches that span multiple networks and touchpoints.
• Balancing user experience. Many retailers limit non-endemic ads to off-site environments or restrict on-site placements to post-purchase pages to avoid cluttering the shopping journey.

How do retailers prevent non-endemic ads from disrupting the shopper experience?

Retailers protect the shopping experience through careful curation and placement restrictions. Many limit non-endemic ads to off-site environments or post-purchase placements rather than inserting them into the core shopping journey.

"Right now, especially from a retail or financial services perspective, non-endemic advertising should come across as more of a rewards-based cross-promotion," said PJ Triboletti, senior vice president of revenue at Fluent. "It could be offering a discount or a free trial for a streaming service, something that's like a 'thank you' to the customer making the purchase."

Large, multicategory retailers have the strongest value proposition because their diverse customer base allows for nuanced audience segmentation. Retailers that match non-endemic advertisers to relevant customer segments based on purchase behavior and intent create complementary rather than intrusive experiences.

What measurement approaches work for non-endemic retail media campaigns?

Measurement is a critical hurdle for non-endemic retail media. The IAB released Retail Media Measurement Guidelines in 2024 covering audience measurement, viewability, incrementality, reporting, and transparency.

"Measurement is table stakes for us," said Cely Moreno-Mosier, senior director of omnichannel marketing and head of retail media partnerships at PepsiCo. "Incremental growth is particularly important as we justify our investments."

Adoption of measurement standards will grow because "retailers will need to prove performance, prove their value to brands," according to Bustos. Data clean rooms and cross-network data collaboration are enabling attribution across touchpoints for non-endemic campaigns.

How should marketers evaluate non-endemic retail media opportunities in 2026?

Marketers evaluating non-endemic retail media opportunities should assess four areas:

• Audience alignment. Does the retailer's shopper base match your target consumer? Multicategory retailers offer broader reach; specialty retailers offer narrower but more qualified audiences.
• Data access and quality. What first-party data can you leverage? Financial services networks bring cross-merchant purchase data, while retailers offer SKU-level granularity, per Marzano.
• Placement options. Understand where non-endemic ads can appear: On-site, off-site, in-store, or post-purchase only. Off-site RMN ad spending is projected to grow 29.6% in 2026, EMARKETER forecasts.
• Measurement capabilities. Prioritize networks that support incrementality testing and adhere to IAB measurement standards.

Start with retailers whose customer profiles align with your target audience rather than chasing the largest networks.

EMARKETER forecast data was current at publication and may have changed. EMARKETER clients have access to up-to-date forecast data. To explore EMARKETER solutions, click here.

We prepared this article with the assistance of generative AI tools and stand behind its accuracy, quality, and originality.