Walmart Marketplace gets dismissed as the small one, and on volume that is fair. It is roughly a tenth of Amazon. The reason to look at it anyway is that almost every number attached to it is moving faster than the equivalent number at Amazon, and the cost of competing there has not caught up yet.
How big Walmart Marketplace actually is#
Walmart Marketplace carries around $65 billion in third-party gross merchandise value. Amazon carries roughly $750 billion. eBay sits near $74 billion and Etsy near $14.8 billion. On size alone, Walmart is a second-tier channel.
The seller count tells a more useful story. Walmart has about 150,000 third-party sellers. Amazon has close to 10 million. That is roughly one seller for every $433,000 of GMV on Walmart against one for every $75,000 on Amazon, which is another way of saying a listing has far less to fight through.
Why the growth rate matters more than the size#
Walmart's third-party marketplace GMV grew a record 50% in the quarter ending April 2026. The seller base grew 32% year on year. Walmart's total retail sales grew about 5% over a comparable period.
A channel growing ten times faster than the business around it is being actively pushed, and the window where it is cheap to enter closes as the seller count climbs. The 32% annual growth in sellers is the clock on that.
Walmart Connect, and why the ads are still cheaper#
Walmart Connect is Walmart's retail media network, the equivalent of Amazon Ads. It reached $6.4 billion in fiscal 2026 after growing 46%, and grew a further 37% in the quarter ending April 2026. Marketplace Pulse puts its growth at about six times the rate of Walmart's retail sales.
The number that matters to an advertiser is the ratio of ad revenue to GMV, because it approximates how much of each sale the platform is extracting in advertising. Amazon's ad revenue equals 8.3% of its GMV. Walmart's equals 4.3%. Advertising on Walmart is close to half as expensive, measured against the sales it sits on top of.
That gap is the opportunity and it is closing. A 46% annual growth rate in Connect revenue against a 50% growth rate in GMV means the ratio is roughly holding for now, but the direction of travel in retail media is one way. We run Walmart alongside Amazon as one retail media budget rather than two separate programmes, because the comparison is the point.
Where Walmart is harder than Amazon#
Approval is not automatic. Walmart reviews applications against business history, catalogue quality and fulfilment capability, and rejects brands that would sail onto Amazon. That gatekeeping is exactly why competition per listing is lower.
- Item setup is stricter. Walmart enforces category-specific attribute requirements that Amazon will let you leave blank.
- The buy box weights price harder. A listing priced above the same item elsewhere on the web can be suppressed outright.
- Fulfilment expectations are tighter, and Walmart Fulfillment Services has narrower category coverage than FBA.
- The advertising console has fewer levers. Less granularity to tune, and less to get wrong.
Most of that difficulty is a data problem, not a strategy problem, which is why the brands that move fastest are the ones whose product content is already clean.
Who should be on Walmart, and who should not#
Walmart suits a brand that already has an Amazon catalogue built, photographed and written, because the marginal cost of listing it again is low and the competition it meets is thinner. It suits everyday consumable and household categories, where Walmart's own shopper base already buys.
It suits brands whose price is genuinely competitive, because the buy box will punish the ones whose price is not.
It does not suit a brand that has not made Amazon work yet. Walmart is an addition, not a rescue, and the same catalogue problems will follow you across. It also does not suit premium or niche categories whose buyer is not already walking a Walmart aisle.
What a sensible first 90 days looks like#
- Weeks one to three: apply, and prepare the catalogue against Walmart's attribute requirements, not Amazon's. This is where most of the real work sits.
- Weeks four to six: list a focused set rather than the whole catalogue. Twenty to fifty of your proven Amazon sellers, priced to win the buy box.
- Weeks seven to nine: turn on Walmart Connect against your own brand terms and your best-converting category terms only. Keep it narrow while the data is thin.
- Weeks ten to thirteen: read the numbers the same way you read Amazon. Total revenue first, then advertising as a share of it, then individual campaigns.
If that produces incremental revenue at a lower advertising cost than Amazon, widen the catalogue. If it does not, the answer is usually price or content, not bids. We do this as Walmart Marketplace work and report it next to Amazon, in the same numbers.