Tech giant contests certification of a collective claim alleging overcharging on cloud software licences used outside its Azure platform as British businesses seek damages.
Microsoft is defending itself against a major legal challenge in the United Kingdom as a £2.1 billion (approximately $2.8 billion) lawsuit advances at London’s Competition Appeal Tribunal, where judges are deciding whether the case can be certified to proceed to trial.
The claim, brought by competition lawyer Maria Luisa Stasi on behalf of nearly sixty thousand British firms, asserts that Microsoft has charged significantly higher fees for running its Windows Server software on rival cloud platforms such as Amazon Web Services, Google Cloud and
Alibaba than it does on its own Azure service.
The legal action argues that such licensing practices created an unfair competitive disadvantage for businesses utilising non-Azure clouds and may have degraded performance on those platforms as part of an “abusive strategy” to leverage Microsoft’s dominant position in the cloud market.
At a preliminary hearing, Microsoft urged the tribunal to dismiss the claim, contending that the case lacks a viable methodology for assessing how damages would be calculated and that it fails to demonstrate a coherent basis for collective action, claims that could halt the litigation at an early stage.
The lawsuit amplifies ongoing scrutiny of Microsoft’s cloud licensing practices, which have been criticised by Britain’s Competition and Markets Authority for disadvantaging competitors and restricting market dynamics, a conclusion that aligns with findings from a CMA report earlier this year.
In response, Microsoft has maintained that the cloud computing market remains highly competitive and dynamic, asserting that its licensing models are legitimate and offer flexibility to customers.
The outcome of the tribunal’s certification decision — expected in coming months — will determine whether the case, one of the largest of its kind in the UK technology sector, can advance to a full hearing, potentially setting a significant precedent for how collective claims against global technology firms are handled in domestic courts.
The legal proceedings also unfold amid parallel regulatory scrutiny in Europe and the United States, where concerns about anti-competitive behaviour in cloud services have attracted broader antitrust investigations.