The Competition Appeal Tribunal (CAT) has approved a £2 billion class action against Microsoft, aimed at compensating approximately 59,000 businesses using the Windows Server operating system in non-Microsoft public clouds. The collective action, led by Maria Luisa Stasi, alleges that Microsoft has overcharged UK entities for Windows Server on competing cloud services. The tribunal dismissed Microsoft's objections and granted a Collective Proceedings Order on an opt-out basis. The class action addresses two main issues: pricing abuse related to the Microsoft Service Provider License Agreement (SPLA) and re-licensing abuse concerning the deployment of Windows Server on Azure versus other cloud providers. The UK Competition and Markets Authority is also investigating Microsoft's software licensing practices within the cloud market. James Hain-Cole from law firm Scott+Scott expressed satisfaction with the tribunal's decision, emphasizing its significance for securing compensation for affected businesses.