Amazon offers to change how it runs its UK marketplace after the CMA investigation
Amazon has offered to change how it runs its UK marketplace after an investigation by the country’s competition watchdog, in a move that could reshape life for thousands of British online sellers.
The Competition and Markets Authority (CMA) said Amazon has made formal commitments not to use third-party seller data to gain an unfair advantage over its own retail business. The promises also aim to give independent sellers a fair shot at the coveted “Buy Box” — the prominent purchase button on product pages — when competing against Amazon’s own offers.
What this means for UK sellers
If the CMA accepts the commitments, an independent trustee will monitor Amazon’s compliance, with the watchdog having a direct say in the appointment. For the roughly 225,000 small and medium businesses selling through Amazon across Europe, the changes could mean fairer competition and potentially lower delivery costs — Amazon also proposed letting marketplace sellers negotiate their own rates with independent Prime delivery providers.
Delayed payment rule
In a separate win for sellers, Amazon has delayed a controversial plan to hold sellers’ funds for more than a week after each sale. The policy, which would have seen payments arrive up to ten days after delivery, sparked outrage among small businesses who warned it could destroy their cash flow. Amazon has now pushed the change back several months for affected sellers.
The bigger picture
Amazon is also expanding its Seller Central dashboard to let merchants manage orders from rival platforms — eBay, Shopify, TikTok, and Walmart — in one place. And new EU customs rules taking effect November 1 will require product identifiers on all goods shipped to EU buyers, a change eBay sellers of used and vintage items say could be difficult to comply with. For UK-based sellers sourcing from platforms like AliExpress and selling on eBay and Amazon, these shifts matter: fairer Buy Box rules, delayed payment holds, and tighter customs paperwork all directly affect margins.
What the Buy Box actually is — and why it decides who eats
Most Amazon shoppers never notice the Buy Box, yet it is the single most valuable button in e-commerce. When several sellers list the same product, only one wins the prominent "Add to Basket" placement — the rest are buried behind a small "other sellers" link that most customers never click. Studies of shopper behaviour consistently show the Buy Box winner takes the overwhelming majority of sales on that listing. The CMA's concern is straightforward: if Amazon's own retail arm wins the box not because it is cheaper or faster but because the referee is also a player, independent sellers compete on an uneven field. The commitment to give sellers a fair shot at the box is therefore not a technicality — it is about who gets seen at all.
Your own data, used against you
The other half of the CMA's case sounds abstract until you translate it into a seller's daily life. Amazon sees everything: which of your products convert, at what price, in which postcodes, in which season. The watchdog's fear is that this marketplace data could inform Amazon's own retail decisions — which products to launch, what price to undercut. The formal commitment says Amazon will not do this. Whether or not any single seller can verify compliance — that is what the independent trustee is for — the principle matters for how you think about platform risk: on any marketplace, your sales data is visible to the platform itself. Never build a business that would collapse if the platform entered your niche tomorrow.
The cash-flow lesson of the delayed payment rule
Amazon's plan to hold seller funds for up to ten days after delivery "sparked outrage" — and rightly so, because for small sellers, cash flow is oxygen. Here is the maths that makes payment holds so dangerous: you pay your supplier today, Amazon pays you in ten days, and in between you must keep buying stock to stay in stock. Every extra day of hold is a day you are financing Amazon's business with your own money. The delay of this policy is a reprieve, not a pardon — sellers should use the extra months to build the buffer they will need if the hold eventually arrives: a rolling cash reserve covering at least two order-to-payout cycles.
A UK seller's action checklist
- Audit your Buy Box share: check which of your listings you win the Buy Box on and which you lose to Amazon Retail. Lost boxes are your most urgent margin problem.
- Diversify off one platform: the same dashboard that now manages eBay, Shopify, TikTok and Walmart orders is Amazon telling you multi-channel is the future — listen.
- Prepare for EU product identifiers: the November 1 customs change is the hard deadline in this story. Catalogue every SKU you ship to the EU and make sure identifiers are attached before the cutoff.
- Build a payout buffer: assume payment holds get longer over time, not shorter. Two full order-to-payout cycles in reserve is the minimum.
- Negotiate delivery: if Amazon opens Prime delivery rates to negotiation, get competing quotes from independent carriers before accepting the default.
Frequently asked questions
What did the CMA actually accuse Amazon of?
The Competition and Markets Authority investigated whether Amazon used third-party sellers' data to give its own retail business an unfair advantage, and whether independent sellers got a fair chance at the Buy Box against Amazon's own offers. Amazon responded with formal commitments rather than a court fight.
What is the Buy Box and why does it matter?
It is the main "buy" button on a product page. When multiple sellers list the same item, only one wins that placement — and the winner gets the vast majority of sales. Losing it can make a listing nearly invisible.
Who checks that Amazon keeps its promises?
If the CMA accepts the commitments, an independent trustee will monitor compliance, with the watchdog having a direct say in who that trustee is.
What was the controversial payment-hold plan?
Amazon planned to hold sellers' funds for more than a week — up to ten days after delivery — before paying out. Small sellers warned it would wreck their cash flow, and Amazon has now delayed the change by several months.
Do these changes affect sellers outside the UK?
The commitments target Amazon's UK marketplace, but the roughly 225,000 small and medium businesses selling across Europe are watching closely — and the EU customs identifier rule affects anyone shipping to EU buyers regardless of location.
