What changed
Tribunal refuses Amazon bid to make sellers above £10m in sales opt in
When
Reasons published November 10, 2026; first trial starts April 25, 2028
Who it affects
UK sellers with a professional account selling to UK buyers, June 2018 to June 2024
What to do
Confirm you are in the class, keep records, answer any Amazon data letter on your terms

Key takeaways

  • On November 10, 2026 the tribunal kept Amazon's roughly 1,000 biggest UK sellers, holding just over 40% of class sales, inside the opt-out £2.7bn claim.
  • Amazon may write to sellers for sales data, but you have no duty to answer without a tribunal order, you get 28 days, and declining cannot affect your account.
  • Archive June 2018 to June 2024 Amazon reports and monthly sales by channel now; the first trial starts April 25, 2028.

Stephan v Amazon: key dates

  1. Claim filed for 200,000+ UK sellers

  2. Opt-out class certified

  3. Opt-out window closes, 2 leave

  4. Rules set for Amazon letters to sellers

  5. Bid to move top 1,000 to opt-in refused

  6. Trial 1 starts

What the tribunal decided on November 10

Amazon asked the Competition Appeal Tribunal to change the collective proceedings order so that every merchant with more than £10m in gross merchandise sales over the claim period would be removed from the opt-out class and would have to opt in to stay in the claim. The tribunal, chaired by Sir Peter Roth, heard the application on September 7 and 8, said at the end of the hearing that it would refuse it, and published its written reasons on November 10 as [2026] CAT 84, according to Law News.

On Amazon's own evidence, the group it wanted to move was about the top 1,000 merchants out of a class of around 214,000, and their combined share was just over 40% of total sales in the class. The order made on November 27, 2025 therefore stands, and the whole class stays opt-out. The opt-out window closed on February 27, 2026, and the tribunal records that only two sellers chose to leave.

What the claim alleges

The claim says Amazon abused a dominant position in marketplace services for UK sellers. These are allegations that Amazon denies and no court has ruled on them. According to the class representative's lawyers at Geradin Partners, the claim alleges that Amazon:

  • Favoured its own retail products over third-party sellers.
  • Favoured Amazon Retail offers when choosing which offer wins the Buy Box.
  • Favoured Fulfilment by Amazon over other fulfilment options.
  • Tied the Prime badge to the use of FBA.
  • Made it harder for sellers to sell cheaper on other platforms.

Who is in the class and what happens next

The class is any UK-domiciled business or individual that used a professional selling account to sell to UK customers on Amazon.co.uk between June 2018 and June 2024. You do not need to register or pay to be included; the claim is funded by Innsworth Capital, which takes a share of any award or settlement. When the claim was filed in 2024, Amazon told TechCrunch: "We are confident that these claims are baseless."

The case is split in two. Trial 1, fixed to start on April 25, 2028 with an estimate of about eight weeks, covers market definition, dominance and whether Amazon abused it. Trial 2 deals with causation, the amount of any loss and how much sellers passed on to shoppers. A consumer claim by Robert Hammond runs alongside it. No money is due to anyone today, and any payout depends on a win or a settlement years from now.

The part most coverage misses: Amazon may write to you

In a ruling dated October 26, 2026 ([2026] CAT 79), the tribunal allowed Amazon to contact class members directly for evidence instead of blocking it, but set conditions. One request it reviewed would ask a sample of 85 sellers for monthly sales value and volume on each other channel (other marketplaces such as eBay, Etsy, OnBuy or Argos, their own website, physical shops, wholesale and social media) from October 1, 2015 to June 26, 2024. The tribunal called that request extremely burdensome.

Any letter Amazon sends must go to your legal team if you have one, link to the tribunal's case page, give the class representative's contact details and give you 28 days to respond. It must also say:

  • You have no obligation to search for or provide anything unless the tribunal orders it, and no such order exists.
  • If Amazon applies for an order, you can oppose it, and Amazon would normally pay your reasonable costs.
  • You may take your own legal advice first.
  • Not responding will not affect your commercial relationship with Amazon.
  • Amazon must protect commercially sensitive data, for example by limiting it to its lawyers and independent economist.

If Amazon writes to you

  • Log the date: you have 28 days
  • No duty to answer without an order
  • Take your own legal advice
  • You may contact the class lawyers
  • Declining cannot affect your account
  • Ask how your data stays confidential

So what: the math for a UK brand

The ruling keeps the largest sellers, and the most money, inside the claim. If about 1,000 merchants hold just over 40% of class sales, the other roughly 213,000 hold under 60%. That means the average top merchant sold around 140 times as much as the average remaining seller (40% / 1,000 against 60% / 213,000), which is why Amazon wanted them to opt in individually. For every seller, the near-term cost is not money but time: a data request covering about 105 months across five channel types is real work for a small finance team.

Worked example: what a data letter could cost you

Illustrative numbers only. A UK home goods seller sells on Amazon, eBay and its own Shopify site. A request like the one the tribunal reviewed would ask for monthly sales value and units for each of those channels from October 2015 to June 2024: 3 channels x 105 months = 315 data points, plus product-level splits for a sample of items sold in more than one place. If each month-and-channel figure takes 10 minutes to find and check, that is about 52 hours of work, roughly 6 to 7 working days. A seller that has kept clean monthly exports can do it in an afternoon; one relying on old logins and lost spreadsheets may not be able to do it at all.

What sellers should do

These steps apply to UK sellers who were active on Amazon.co.uk between June 2018 and June 2024.

  • Owner: confirm membership. Check you were UK domiciled, used a professional account and sold to UK buyers in the window. Metric: a yes or no recorded in your company file.
  • Finance lead: archive Amazon settlement reports, fee invoices and business reports for June 2018 to June 2024, plus monthly sales by channel back to October 2015. Metric: one folder with every month present.
  • Owner or legal: if a letter from Amazon or its lawyers arrives, log the date, note the 28-day window and get advice before replying. You can also contact the class representative's lawyers named in the letter. Metric: a decision logged within 28 days.
  • Account manager: keep running the account as normal and record any account health change in the weeks after you receive or decline a request. Metric: Account Health rating stable, see our Amazon account health guide.
  • Marketplace lead: since the claim concerns the Buy Box and FBA, track your own Buy Box percentage and FBA versus seller-fulfilled mix monthly. Metric: Featured Offer percentage in Business Reports.

When this does not apply

Sellers based outside the UK, sellers who only joined after June 2024 and the two who opted out are not in this class. US sellers have separate litigation; read our note on the US price parity class certification. Nothing here is legal advice, and the allegations are unproven.

Where PPC Spider helps

PPC Spider is a marketplace agency for brands selling on Amazon and other marketplaces. Our Amazon account management team keeps clean monthly channel reports, which makes requests like this far easier to answer, and a free Amazon audit shows your Buy Box, fee and FBA position today. Follow the Amazon policy updates channel for the next ruling.

Sources

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