Microsoft Corp. must face a UK class action trial over allegations it abused its dominant position in the market to overcharge businesses that used the Windows Server operating system and Azure, an antitrust tribunal has ruled.
Judges at London’s Competition Appeal Tribunal said the lawsuit on behalf of around 59,000 businesses and organizations had “reasonable prospects of success.” If successful, the lawsuit could see a payout of more than £1.7 billion ($2.3 billion), the claimants have estimated.
Microsoft will appeal the decision and also dispute the underlying allegations, the company’s spokesperson said on Wednesday. “Today’s decision makes no final determination on those claims.”
The ruling comes weeks after the UK’s antitrust watchdog started an investigation into Microsoft’s business software ecosystem to decide whether licensing practices for products such as Word, Excel and Copilot need tighter regulation.
The evidence from the watchdog’s investigation could help prove that Microsoft’s licensing practices distorted competition and caused loses to cloud computing users, the judges said in the ruling.
“For years, Microsoft’s practices have had real financial impact on both public and private organizations,” Maria Luisa Stasi, the lead representative for the claimants, said.
The claim is funded by LCM Funding UK Ltd, a unit of Australian litigation financing firm Litigation Capital Management Ltd..
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Published on April 22, 2026