Amazon was denied permission to appeal the approval of lawsuits from customers and shops in the UK

Amazon has lost its latest attempt to dismiss two major lawsuits in the United Kingdom worth up to £4 billion ($5.41 billion). The cases accuse the company of abusing its dominant market position.

One case was filed by Andreas Stephan, a competition law academic, on behalf of more than 200,000 third-party retailers. The claim is valued at up to £2.7 billion. The lawsuit alleges that Amazon unfairly manipulates its “Buy Box” feature — the section on a product page that highlights the main seller — to benefit itself. It also claims that Amazon favors products that use its own logistics centers and delivery services.

A separate case was brought by consumer advocate Robert Hammond on behalf of millions of Amazon customers. This lawsuit is valued at up to £1.3 billion and makes similar allegations that Amazon abused its dominant position in the market.

Amazon has previously denied the claims, saying they have no merit. The company argued that the cases should not move forward, stating that the economic methods used to prove the claims were flawed.

However, the Competition Appeal Tribunal certified both cases last year on an “opt-out” basis. This means that affected retailers and consumers are automatically included in the lawsuits unless they choose to withdraw.

Amazon then asked for permission to appeal that decision, but the Court of Appeal refused permission on Thursday.

Amazon has not yet responded to requests for comment.