Retail media is no longer a rounding error on DTC ad budgets. U.S. retail media spend crossed $62 billion in 2025, according to eMarketer, and the two platforms capturing the lion’s share of that growth are Amazon DSP and Walmart Connect. For brands already selling on both marketplaces — or deciding where to double down — the choice of which platform deserves incremental budget is increasingly consequential. This comparison breaks down where each platform actually delivers in mid-2026, using public financial disclosures, third-party measurement data, and operator-reported ROAS benchmarks.
What Does the Market Share Picture Actually Look Like?
Amazon’s advertising services revenue hit $56.2 billion in full-year 2025, up 18% year-over-year, cementing its position as the third-largest digital advertising platform in the U.S. behind only Google and Meta. Walmart Connect, by contrast, reported approximately $4.4 billion in global ad revenue for FY2026 (ending January 2026), a figure that represents 28% growth year-over-year — the fastest growth rate of any major retail media network by percentage.
The gap is enormous in absolute dollars, but the trajectory tells a more nuanced story. Walmart Connect’s growth rate is outpacing Amazon Ads by roughly 10 percentage points annually, and Walmart’s total addressable audience — 255 million weekly shoppers across physical stores and digital channels — gives it a reach argument that pure-play e-commerce competitors cannot replicate.
| Metric | Amazon DSP | Walmart Connect |
|---|---|---|
| 2025 Ad Revenue (Global) | $56.2B | $4.4B |
| YoY Growth Rate | ~18% | ~28% |
| Minimum Managed Spend (DSP) | $50,000/month (managed); self-serve lower | $25,000/month (managed) |
| Self-Serve Access | Yes (Sponsored Products, Brands, Display) | Yes (Sponsored Search, Display) |
| Off-Platform Audience Reach | Strong (Fire TV, Alexa, third-party web) | Growing (Roku partnership, in-store screens) |
| Closed-Loop Attribution | Yes (Amazon purchases only) | Yes (online + in-store) |
| Average Sponsored Product CPC (Q1 2026) | $1.42 | $0.61 |
| Median Sponsored Search ROAS (CPG) | 4.1x | 5.8x |
| AI Bid Automation | Yes (Performance+, Dynamic Bidding) | Yes (Smart Bidding, launched Q4 2025) |
| Third-Party DSP Access | Yes (via Amazon DSP API) | Yes (The Trade Desk partnership) |
How Do the CPC Economics Compare for Mid-Market Brands?
The single most operationally relevant gap between the two platforms right now is cost-per-click. Downstream Commerce’s Q1 2026 benchmark report — which aggregated data from 1,400 brand accounts — pegged average Amazon Sponsored Products CPC at $1.42, versus $0.61 for Walmart Connect Sponsored Search. In competitive categories like supplements and home goods, Amazon CPCs regularly breach $3.00, while Walmart equivalents stay below $1.20.
That math matters enormously for brands with thin gross margins. A CPG brand operating at 45% gross margin needs meaningfully lower acquisition costs to sustain profitable ad spend. Walmart Connect’s lower CPCs are partly a function of lower advertiser competition — there are simply fewer brands bidding — but also reflect Walmart’s historically more conservative auction mechanics.
“We shifted 22% of our Amazon Sponsored Products budget to Walmart Connect in Q1 and saw blended ROAS go from 3.8x to 4.9x on that incremental dollar. The CPCs are just dramatically cheaper for the same shopper intent,” said Marcus Feldman, VP of Growth at Revive Wellness Brands, a DTC supplement company with $38M in annual Walmart marketplace GMV.
That said, Amazon’s volume advantage is real. A $0.61 CPC on Walmart Connect means nothing if daily impression volume caps out at 40,000 for a niche product category. Amazon’s auction depth means brands can scale spend far higher before hitting inventory constraints on the advertising side.
Which Platform Has Better Audience Data and Off-Platform Reach?
Amazon DSP’s off-platform capabilities remain its most differentiated asset for brand-building budgets. Fire TV reaches 230 million connected TV devices globally. Alexa’s purchase intent signals feed audience segments that no external DSP can replicate. Amazon’s acquisition of IMDb gives it premium video inventory that Walmart Connect simply cannot match today.
Walmart Connect is trying to close this gap through partnerships rather than owned inventory. Its deepened integration with The Trade Desk — announced in March 2026 — now allows advertisers to activate Walmart’s first-party shopper data (covering 144 million U.S. households) programmatically across The Trade Desk’s publisher network. The Roku partnership, formalized in late 2025, brings Walmart purchase data into CTV targeting for the first time.
“Walmart’s first-party data is genuinely underutilized by most brands. 144 million households, skewing toward suburban and rural grocery buyers — that’s a different demographic than Amazon Prime, and for our category, it converts,” said Priya Venkatesan, Head of Retail Media at Tinuiti, which manages over $900 million in annual retail media spend across both platforms.
Amazon’s closed-loop attribution still covers only Amazon purchases, which matters less as more DTC brands drive off-Amazon consideration. Walmart Connect’s in-store attribution — connecting a digital ad impression to a physical Walmart register transaction — is a capability Amazon cannot credibly offer at scale.
How Does AI-Powered Bid Automation Stack Up on Each Platform?
Amazon’s Performance+ campaign type, which launched broadly in early 2025, uses machine learning to automatically allocate budget across Sponsored Products, Sponsored Brands, and display placements in a single campaign structure. Operators running Performance+ are reporting 12–18% lower cost-per-acquisition versus manually-managed campaigns in Tinuiti’s Q2 2026 benchmark data, though the trade-off is reduced placement-level transparency.
Walmart Connect launched its own Smart Bidding suite in Q4 2025, rolling it out broadly to self-serve advertisers by February 2026. The system optimizes bids in real time toward a target ROAS or target CPA, drawing on Walmart’s purchase graph. Early adopters report that Smart Bidding works well for high-velocity SKUs but struggles with new product launches where purchase history is thin — a known limitation Amazon’s system also exhibits.
- Amazon Performance+: Best for brands with 12+ months of sales history and broad SKU catalogs; automation benefits compound with data volume
- Walmart Smart Bidding: Outperforms manual bidding fastest in grocery, consumables, and private-label categories where Walmart’s purchase graph is deepest
- Third-party tooling: Platforms like Pacvue and Perpetua now support both Amazon and Walmart Connect natively, allowing unified bid management across both networks from a single dashboard — a meaningful operational advantage for agencies managing both
Which Platform Should Operators Prioritize Budget Allocation Toward in H2 2026?
The honest answer depends heavily on category and brand maturity. Amazon DSP and Sponsored Products remain non-negotiable for brands whose primary revenue is on Amazon — cutting that spend risks losing search rank and Buy Box positioning as much as it risks losing direct conversions. For brands already generating more than $5M in Amazon GMV annually, the advertising flywheel is too embedded to unwind.
The more interesting question is where incremental budget should go. The consensus among agency leaders interviewed for this piece is that Walmart Connect is delivering outsized returns for brands willing to treat it as a primary channel rather than an afterthought. The CPC discount is real, the in-store attribution capability is unique, and the competitive density is still low enough that well-structured campaigns generate ROAS that Amazon Sponsored Products delivered three years ago.
“The brands winning on Walmart Connect right now are the ones who stopped treating it like Amazon Lite. Different shopper, different creative, different bidding strategy. The ones copy-pasting their Amazon playbook are leaving a lot on the table,” said Jordan Estes, SVP of Marketplace Strategy at Digital Commerce Partners.
The regulatory environment is also worth tracking. The FTC’s ongoing scrutiny of Amazon’s advertising practices — specifically around self-preferencing of Amazon’s own private label products in sponsored placements — introduces a tail risk that Walmart Connect does not carry in the same form. No enforcement action has landed as of publication, but the overhang is real for brands modeling long-term platform dependency.
What Are the Practical Access Requirements for Each Platform?
Access mechanics differ in ways that matter for smaller operators. Amazon’s self-serve Sponsored Products requires no minimum spend and is available to any seller or vendor with an active listing. Amazon DSP managed service historically required $50,000 per month in minimum commitment, though Amazon has pushed self-serve DSP access more aggressively through its console and via third-party API partners like Perpetua, lowering the effective entry point.
Walmart Connect’s managed service entry point sits at approximately $25,000 per month — a lower barrier than Amazon DSP managed. Self-serve Sponsored Search on Walmart requires only an active Walmart Marketplace seller account and no minimum spend, making it accessible to brands generating as little as $50,000 annually on the platform.
The operational verdict for mid-market brands in mid-2026: run both, but build Walmart Connect expertise now while CPCs are still cheap and competition is still thin. The window for outsized efficiency on Walmart Connect is real, but it will not stay open indefinitely as more sophisticated advertisers migrate budgets in that direction. The brands building Walmart Connect competency today — in creative, bidding strategy, and audience segmentation — are positioning for a structural advantage that mirrors what early Amazon advertisers captured between 2018 and 2021.
