Microsoft Fights £2.1 Billion UK Suit Over Cloud Licensing

At a December 11 hearing in London, Microsoft asked the Competition Appeal Tribunal to dismiss a proposed group action that accuses the company of charging inflated licenses for Windows Server when the software is run on rival cloud platforms. The suit, brought by competition lawyer Maria Luisa Stasi on behalf of nearly 60,000 U.K. businesses, alleges that Microsoft made alternatives such as Amazon Web Services, Google Cloud Platform and Alibaba Cloud comparatively more expensive, effectively nudging customers to Microsoft’s Azure service.

Stasi, identified in some coverage as head of law and policy for the digital rights group Article19, seeks permission to proceed as a collective claim that Reuters and other outlets reported could amount to £2.1 billion in damages. Other media described the case as seeking in excess of £1 billion. Those differing figures were presented in press coverage at the hearing and reflect variances in how the damages package has been characterized in public reports.

The plaintiff’s legal team, represented at the hearing by lawyer Sarah Ford, told the tribunal that Microsoft’s licensing approach amounted to an “abusive strategy” that overcharged thousands of businesses. The case rests on an allegation that Microsoft used its dominance in server operating systems to extract higher fees for deployments on non Azure clouds, thereby reducing competition in commercial cloud markets.

Microsoft responded with a procedural challenge, urging the tribunal to throw out the claim at an early stage. The company argued the claim “does not set out a proper blueprint for how the tribunal will work out any alleged losses” and therefore cannot proceed as presented. Those submissions focus on the methodology for calculating damages and on whether the proposed class shares common and identifiable losses that can be resolved collectively.

The procedural posture of the hearing means the tribunal must first decide whether to certify Stasi’s action as a representative group claim. If permission is granted, the case would move into a substantive phase in which parties would exchange evidence, litigate liability and test methods for quantifying losses across thousands of customers. If permission is denied, individual claimants might still pursue separate actions but would face higher litigation costs.

The tribunal proceedings unfold against a backdrop of heightened regulatory attention to cloud competition. Authorities in the U.K., the European Union and the United States have opened or are conducting probes into whether large software vendors use licensing to advantage their own cloud services. Legal observers say the outcome of the certification stage could affect not just this case but broader enforcement strategies, including the viability of collective litigation as a remedy in complex technology markets.

For now the dispute will turn on legal thresholds for group claims and the tribunal’s assessment of whether the plaintiffs have marshalled a coherent damages model. A decision on certification is expected in the months ahead, setting the timetable for what could become a benchmark competition case in the cloud era.