MICROSOFT MUST FACE £2 BILLION LEGAL ACTION FOR OVERCHARGING THOUSANDS OF UK BUSINESSES
The Competition Appeal Tribunal (CAT) has ruled to certify a £2 billion legal opt-out collective action against Microsoft over its cloud computing and software practices.
The court case, brought by leading digital markets regulation expert Dr Maria Luisa Stasi, accuses Microsoft of overcharging UK businesses and organisations that use its Windows Server on rival cloud services. The case seeks compensation for approximately 59,000 businesses and organisations.
In its ruling, the CAT dismissed Microsoft’s arguments against certification and granted a Collective Proceedings Order (CPO) on an opt-out basis, allowing the case to head to trial. The CPO allows businesses to pursue legal action against Microsoft as a group, as opposed to filing individual claims. The CAT also concluded in the ruling that the claim “comfortably crosses the hurdle of having a real prospect of success.”
The landmark ruling to progress the claim to trial means UK businesses that have used Windows Server on rival cloud services should visit the claim’s website to find out about compensation: https://ukcloudclaim.com/register/
Commenting on the ruling, Dr Maria Luisa Stasi said:
“Today’s ruling is an important moment for the thousands of organisations impacted by Microsoft’s conduct and in ensuring that a critical sector of the economy is innovative and open. For years, Microsoft’s practices have had real financial impact on both public and private organisations. I’m now looking forward to preparing for trial and getting their money back on their behalf.”
James Hain-Cole, Partner at Scott+Scott leading on the case against Microsoft, commented:
“We are very pleased with the Tribunal’s decision, including its confirmation that Dr Stasi’s action should proceed on an opt-out basis, as sought in her application. Certification of this claim is a pivotal step in securing compensation for thousands of businesses and organisations. The decision illustrates the importance of the regime for UK businesses who, like consumers, require and deserve the access to justice that it was designed to offer.
Looking ahead to the trial, we are proud to be supporting Dr Stasi’s efforts to provide access to justice for those organisations that have suffered as a result of Microsoft’s anti-competitive practices, which remains the target of competition regulators around the world.”
Microsoft increasingly probed for its cloud and licensing practices
Microsoft’s dominance and anticompetitive practices in its cloud and server operating systems are being subject to increasing scrutiny from regulators around the world.
- In July 2025, the UK’s competition regulator, the Competition Markets Authority (CMA) published its final report in its investigation of the cloud computing market, finding that Microsoft charges higher prices for software products when used on rival cloud computing services like AWS and Google. A decision on imposing conduct requirements on Microsoft remains pending.
- In November 2025, the European Commission announced another investigation to assess whether Microsoftshould be designated as a gatekeeper for its cloud computing services under the Digital Markets Act (DMA).
- In January 2026, the Brazilian Council for Economic Defence (CADE) officially launched an Administrative Inquiry into Microsoft’s cloud computing and software licensing practices. Building on the CMA’s findings on Microsoft’s adverse impact on the UK and Europe, the inquiry will investigate Microsoft’s impact on Brazil.
- In January 2026, the Swiss Competition Commission (COMCO) launched a Preliminary Investigation into Microsoft’s licensing practices in Switzerland, following complaints from businesses and government agencies.
- The US Federal Trade Commission (FTC), in February 2026, issued civil investigative demands to companies that compete with Microsoft as to whether Microsoft makes it difficult for customers to use Windows, Office and other products on competing cloud services.
- On February 25 2025, Japan’s Fair Trade Commission raided Microsoft Japan’s offices as part of an investigation into whether it improperly restricted customers of its Azure platform from using rival cloud services.
- On 31 March 2026, the UK Competition and Markets Authority announced it would launch a Strategic Market Status investigation into Microsoft, probing its software licensing practices in the cloud market. This investigation builds on a previous investigation concluded in July 2025, concerning Microsoft’s anti-competitive behaviour in cloud computing.