Stephenson Harwood Takes on Amazon in Major UK Class Action Over Pricing Practices
By Sarah Mitchell
August 23, 2025
London, UK – International law firm Stephenson Harwood has launched a landmark opt-out class action against e-commerce giant Amazon, representing the Association of Consumer Support Organisations (ACSO) in a case that could impact over 45 million UK consumers. Filed with the UK’s Competition Appeal Tribunal (CAT) on August 14, 2025, the lawsuit alleges that Amazon’s anti-competitive pricing policies have inflated costs for customers purchasing from third-party sellers on its platform, potentially leading to millions in compensation.
Allegations of Anti-Competitive Conduct
The collective action, spearheaded by Stephenson Harwood partner Genevieve Quierin, claims that Amazon’s price parity policies, enforced between August 2019 and August 2025, restricted third-party sellers from offering lower prices on other platforms, including their own websites. According to ACSO, these policies stifled competition, allowing Amazon to charge higher fees to sellers, which were then passed on to consumers in the form of elevated prices. The lawsuit argues that this practice constitutes an abuse of Amazon’s dominant market position, resulting in UK consumers paying “millions more than they should have” for products.
Quierin stated, “Amazon appears to have circumvented previous regulatory interventions targeting its pricing policies and is now implementing policies which we contend are anti-competitive, to the detriment of UK consumers.” She emphasized the firm’s commitment to securing compensation for affected consumers, noting that the opt-out nature of the claim automatically includes all UK buyers who purchased from third-party sellers on Amazon’s UK marketplace during the specified period, unless they choose to opt out.
A Growing Trend of Class Actions
This lawsuit marks Stephenson Harwood’s first foray into opt-out class actions before the CAT, a move enabled by recent changes in UK law that have facilitated large-scale consumer claims. The case follows a £2.6 billion group action certified earlier this year against Amazon, brought by over 200,000 third-party sellers alleging similar anti-competitive conduct, including unlawful use of their data.
The ACSO lawsuit is backed by a litigation funder, a member of the Association of Litigation Funders, though their identity remains undisclosed. The legal team, led by Quierin, includes partners Tim Knight, Alex Athanasopoulos, Katelyn Iacono, Mikaela Hristova, and Jay Kim, alongside Ben Lask KC, Luke Kelly, and Jenn Lawrence of Monckton Chambers, and economic experts from The Brattle Group.
Amazon’s Response and Global Scrutiny
Amazon has dismissed the claims as “without merit,” asserting confidence that the legal process will vindicate its position. A spokesperson highlighted Amazon’s competitive pricing, citing independent analysis by Profitero that ranks the company as the UK’s lowest-priced online retailer for five consecutive years.
The lawsuit adds to Amazon’s mounting legal challenges globally. The company’s pricing practices are under scrutiny by regulators in Germany, Japan, Canada, and the United States, with the US Federal Trade Commission (FTC) currently investigating similar allegations. In 2022, California filed a lawsuit against Amazon over its pricing policies, with a trial expected in 2026. Additionally, Amazon faces separate class actions in the US over issues ranging from biometric data handling to refund practices and Prime subscription cancellations.
Implications for Consumers and the Market
The case could have far-reaching implications for both consumers and the e-commerce landscape. If certified by the CAT, it will proceed on behalf of an estimated 45 million UK consumers, potentially setting a precedent for how dominant online marketplaces are regulated. ACSO’s founder, Matthew Maxwell-Scott, emphasized the importance of collective actions in challenging corporate behavior, stating, “Millions of people in the UK make purchases on Amazon every day. Despite the company’s assurances that it is ‘customer-obsessed,’ we consider there are strong grounds to argue that UK consumers have paid higher prices because of Amazon’s pricing policies.”
Posts on X reflect growing public interest, with users debating Amazon’s market dominance and the potential for consumer redress. One user noted, “Amazon’s price policies have been squeezing sellers and buyers for years. This lawsuit could shake things up.” Another expressed skepticism, stating, “Good luck taking on Amazon’s legal army. They’ll fight this to the end.”
What’s Next?
The CAT will hold a hearing to determine whether the case can proceed and if ACSO is suitable as the class representative. If approved, the lawsuit could lead to significant compensation for UK consumers, though the exact value of the claim has not been disclosed. For Amazon, a loss could prompt changes to its pricing policies and increase regulatory pressure worldwide.
As the legal battle unfolds, Stephenson Harwood’s bold move signals a new era of accountability for tech giants. With consumer advocacy groups and regulators closing in, Amazon’s business practices will remain under intense scrutiny, potentially reshaping the rules of e-commerce competition.
Sarah Mitchell is a legal correspondent covering consumer rights and corporate accountability.