Amazon Ads vs. Walmart Connect in 2026: Which Retail Media Network Wins?

For most of the last decade, “retail media” meant one thing: Amazon Advertising. But heading into the back half of 2026, the gap between Amazon Ads and Walmart Connect has compressed enough that agency buyers, DTC founders, and marketplace operators are genuinely weighing how to split budgets — not just defaulting to the incumbent. This head-to-head examines the two platforms across ROAS benchmarks, audience data quality, ad format depth, measurement transparency, and where each genuinely pulls ahead.

What Do the Numbers Actually Say About Scale and Reach?

Amazon Advertising generated an estimated $56.2 billion in ad revenue in 2025, according to eMarketer’s March 2026 report, making it the third-largest digital ad platform in the U.S. behind Google and Meta. Amazon commands roughly 77% of all U.S. retail media ad spend. Walmart Connect, by contrast, posted approximately $4.4 billion in ad revenue over the same period — a 38% year-over-year increase that is remarkable by any standard, but still a fraction of Amazon’s footprint.

What Walmart Connect lacks in raw scale, it partially offsets with omnichannel reach that Amazon structurally cannot replicate. Walmart operates 4,600-plus physical U.S. stores and services more than 255 million customer visits weekly across digital and physical touchpoints. For brands in grocery, home goods, baby, and consumables, that in-store attribution capability — Walmart’s Closed Loop Attribution system linking ad exposures to in-store purchases via first-party Walmart+ data — is a legitimate differentiator that Amazon’s DSP simply cannot match.

“We shifted 18% of our Amazon Sponsored Products budget into Walmart Connect DSP in Q1 2026 and saw ROAS that was within 12% of Amazon’s — with CPCs running about 40% cheaper on the same SKU categories. The efficiency story is real.” — Mara Steinfeld, VP of Growth, Bonafide Health

How Do the Ad Formats and Self-Serve Tools Stack Up?

Amazon’s ad stack remains the most mature in the retail media industry. Sellers and vendors can access:

• Sponsored Products — keyword and ASIN-targeted CPC ads appearing in search and PDP
• Sponsored Brands — headline search and video units with brand store linking
• Sponsored Display — audience retargeting on and off Amazon, including streaming TV via Freevee
• Amazon DSP — programmatic access to Amazon’s first-party audience segments across the open web, Twitch, Fire TV, and publisher inventory
• AMC (Amazon Marketing Cloud) — SQL-based clean room analytics for path-to-purchase modeling

Amazon’s AMC rollout has been the most consequential platform development of the past 18 months for sophisticated sellers. Third-party tools like Pacvue, Perpetua, and Scale Insights now natively integrate AMC query outputs, allowing agencies to build multi-touch attribution models that were impossible two years ago. The limitation: AMC requires meaningful technical lift and a media budget of at least $50,000/month to generate statistically meaningful cohort sizes, effectively gatekeeping its best insights to enterprise-tier operators.

Walmart Connect’s format library has expanded significantly since 2024 but remains narrower:

• Sponsored Products — now available fully self-serve via the Walmart Ad Center
• Sponsored Brands — launched broadly in late 2025, with video units still in limited rollout as of June 2026
• Display and OTT — available through managed service for budgets above $25,000/month; Walmart’s Luminate data platform powers audience segments
• In-store digital — Walmart’s in-store TV network (covering 170,000+ screens) is increasingly bundled into DSP packages

“The Walmart Ad Center self-serve interface is where Amazon Seller Central was in 2019 — functional, but the bulk editing tools and automated bidding logic are about two generations behind what Amazon offers today. That’s the honest assessment.” — Jason Terk, Director of Marketplace Strategy, Tinuiti

Which Platform Has Better First-Party Data and Measurement?

This is where the comparison gets genuinely competitive. Amazon’s first-party data covers an estimated 170 million U.S. Prime members with transaction history, browse behavior, and streaming data stitched together. The signal density is unmatched in retail media. But that scale comes with opacity — Amazon’s walled garden means advertisers see aggregated attributed sales, not true incrementality, unless they invest in AMC or incrementality testing through tools like Measured or Northbeam.

Walmart Connect’s Luminate platform, which was expanded to advertising clients in 2025, offers something legitimately differentiated: deterministic purchase data from Walmart+, Walmart.com, and 4,600 physical stores matched against ad exposures. For brands where omnichannel attribution matters — a CPG brand running display ads to drive grocery aisle pickup, for example — Walmart’s closed-loop measurement is more complete than Amazon’s. Walmart claims average closed-loop attribution match rates of 68% for Walmart+ members on display campaigns, a number several agency buyers have told Ecommerce Times they can roughly corroborate from their own client data.

The caveat: Walmart+ has approximately 22 million members as of Q1 2026 (per Bloomberg Intelligence), compared to Prime’s 170 million. The data is cleaner for the audience it covers; it just covers far fewer people.

What Are the Real CPCs and ROAS Benchmarks in 2026?

Benchmark data from Pacvue’s Q1 2026 Retail Media Report and Tinuiti’s Marketplace Intelligence unit provides a useful baseline:

The CPC gap is the most tactically relevant data point for smaller sellers. A brand spending $15,000/month on Amazon Sponsored Products is buying roughly 12,700 clicks at average Q1 CPCs. That same budget on Walmart Connect buys approximately 23,800 clicks — nearly double the traffic volume, at a lower conversion rate but often comparable or better cost-per-acquisition in select categories.

Which Platform Should Different Operator Types Prioritize?

The honest answer is that for most sellers, this is not an either/or decision — it’s a budget weighting question. But the calculus differs meaningfully by operator type:

• Amazon-native sellers under $5M annual GMV: Amazon Ads remains the default. The self-serve tooling, keyword volume, and customer intent are simply deeper. Walmart Connect’s minimum daily budgets and higher managed-service thresholds create friction for small operators.
• CPG and grocery brands with physical retail presence: Walmart Connect’s in-store attribution is a genuine reason to shift meaningful budget — especially for brands running Walmart+ member promotions or rollbacks. The omnichannel closed loop justifies the premium on CPCs relative to pure digital ROAS comparisons.
• DTC brands expanding to marketplace: Start with Amazon, but pilot Walmart Connect Sponsored Products as a lower-CPC testing ground. Several brands report using Walmart as a creative and keyword testing environment before scaling winning structures back to Amazon.
• Enterprise advertisers running DSP: Run both. Amazon DSP’s audience depth and third-party publisher network remains superior for prospecting at scale. But Walmart’s Luminate-powered segments are producing strong results in household consumables and baby categories where the Walmart shopper skews high-purchase-frequency.

“We tell our clients to think of Walmart Connect as Amazon 2019 — you’re getting inefficiency arbitrage right now because the auction isn’t saturated yet. That window will close. The brands loading up now are going to have a significant advantage in 2027.” — Rhea Calloway, SVP of Retail Media, Bobsled Marketing

What Are the Biggest Risks and Gaps for Each Platform in the Second Half of 2026?

Amazon’s primary structural risk is auction inflation. Average Sponsored Products CPCs rose 14% year-over-year in Q1 2026, driven by increased seller count and Amazon’s own first-party and vendor ad purchasing behavior. For brands in competitive categories — supplements, home goods, electronics accessories — CPCs above $2.50 are making profitability increasingly difficult without AMC-level incrementality modeling to justify spend.

Amazon’s second risk is regulatory exposure. The FTC’s ongoing antitrust scrutiny of Amazon’s advertising and marketplace practices — the case filed in 2023 is still working through federal courts — creates uncertainty around whether Amazon’s self-preferencing of first-party products in sponsored placements will face structural remedies. Most practitioners aren’t expecting near-term operational changes, but enterprise legal teams are flagging it as a 2027-2028 risk horizon.

Walmart Connect’s biggest gap remains its managed-service dependency for anything beyond basic Sponsored Products. Brands wanting display, OTT, or in-store digital integration still need to route through Walmart’s sales team, with minimum commitments that price out most Shopify-native DTC brands. The Walmart Ad Center self-serve interface also still lacks bulk editing, advanced dayparting, and the automated bidding sophistication that Amazon sellers have taken for granted for years.

The platform trajectory, however, favors Walmart Connect. Its 38% YoY ad revenue growth, the continued expansion of Walmart+ membership, and a vendor roadmap that includes full DSP self-serve access by Q4 2026 (per Walmart’s March 2026 ad partner briefing) suggest the gap in tooling will continue closing. For operators willing to invest in building Walmart Connect competency now, the efficiency window is real — and narrowing.