A £2.1 billion ($2.8bn) lawsuit levied against Microsoft went to the Competition Appeal Tribunal (CAT) yesterday, to see if it can proceed to a full trial in 2026.

The case was filed in December 2024 by Dr. Maria Luisa Stasi, and accuses Microsoft of overcharging businesses that use its Windows Server on Google Cloud, Amazon Web Services, or Alibaba Cloud, seeking $2.8bn to compensate the companies and organizations impacted.

In October, Microsoft told DCD that the lawsuit was an "opportunistic attempt" to "piggy-back on baseless complaints Google has made and which we’ve all addressed or rebutted.

"We enable our cloud competitors to profit by offering our products to their cloud customers, and our competitors set their own prices when they do this.”

During yesterday's hearing, which was held to assess the viability of the case heading to trial next year, Microsoft argued that the case lacks a proper blueprint as to how alleged losses would be paid back and asked that it be thrown out.

Stasi's lawyer, Sarah Ford, meanwhile, said that thousands of businesses had been overcharged, and Microsoft uses a "coherent abusive strategy" to maintain a dominant position in the market.

For now, no decision has been made regarding whether the CAT will allow Collective Proceedings Order, with deliberations sometimes taking weeks or months to be concluded.

DCD has reached out to Microsoft for comment.

Earlier this year, an investigation by the UK's Competition and Markets Authority (CMA) concluded that the cloud computing market was not operating in an effectively competitive manner, noting specifically that Amazon Web Services and Microsoft merited greater investigation to determine if they have "strategic market status." Microsoft's software licensing practices were specifically called out.

In November, the US launched an investigation into both AWS and Microsoft.