The hyperscalers’ hold on the global, multibillion-pound cloud computing market has come under repeated scrutiny over the past couple of years from governments, regulators and trade bodies.
In broad terms, the purpose of this scrutiny is to ascertain if the market’s biggest hitters, which include Amazon Web Services (AWS) and Microsoft, are behaving in anti-competitive ways to grow and protect their market-leading positions.
Where Microsoft’s activities are concerned, there is one particular behaviour the company participates in that has been singled out for criticism in many of these investigations. That behaviour concerns its widely criticised practice of charging customers more for wanting to run and host its software (namely Windows Server) in competing cloud environments.
It is claimed the tactic can make it cost-prohibitive for enterprise cloud users to run Microsoft’s software anywhere but on the software giant’s own public cloud platform Azure, which could potentially give it an unfair advantage when it comes to building its share of the cloud infrastructure market.
As previously reported by Computer Weekly, the UK communications market regulator Ofcom raised a red flag about the issue in its October 2023 UK cloud market study, which paved the way for a two-year follow-up investigation by the UK Competition and Markets Authority (CMA), which concluded in July 2025.
The CMA’s 637-page investigative report devoted more than 170 pages to discussing Microsoft’s cloud licensing habits in detail, and concluded the company’s practices are “adversely impacting the competitiveness of AWS and Google [specifically] in the supply of cloud services” and “reducing competition in [the] cloud services market”.
The CMA also stated that Microsoft’s licensing practices, “in combination with other features we have identified”, are further limiting the choice and “attractiveness” of alternative products and suppliers.
As a result, the CMA recommended that Microsoft be subject to targeted and bespoke interventions to remedy the impact the company’s behaviour is having on the UK cloud infrastructure services market as a whole.
At the time of writing, it is unclear when exactly in 2026 the CMA’s recommendations are likely to come into effect and what the long-term impact of them will be on Microsoft’s behaviour.
Meanwhile, in November 2025, the European Commission launched a separate probe into Microsoft’s hold on the continent’s cloud market, which is expected to culminate in a final report within 18 months.
In the meantime, work is underway to secure financial recourse for UK businesses in the form of a burgeoning group legal action, which is open to any firm that fears it may have paid more “at any point since December 2018” to use Microsoft’s software in the AWS, Google or Alibaba public clouds.
Overseeing this effort is Italian competition lawyer, Maria Luisa Stasi, with the support of complex disputes resolution firm, Scott+Scott. They claim UK firms affected by Microsoft’s cloud licensing practices could be collectively owed £2bn in compensation.
The first round of court hearings on the issue are due to take place at the UK Competition Appeal Tribunal (CAT) on 11 December 2025.
The hearing’s purpose is to determine if a collective proceedings order (CPO) for the matter should be granted. This is a legal mechanism that allows a collective action involving multiple claimants with similar issues to band together in a single legal action against an entity (in this case, Microsoft) on anti-competition grounds.
If the CAT grants the order, that will certify Stasi’s claim and means her case against Microsoft can proceed to full trial, putting the businesses that have allegedly been left financially disadvantaged by Microsoft’s actions one step closer to being compensated.
The case itself has been more than a year in the making, as news that Stasi had submitted a claim for consideration to CAT first emerged in December 2024, with it being confirmed at the time that this claim would take the form of an “opt-out collective action”.
This approach makes it possible for class actions, such as Stasi’s case, to proceed against a company like Microsoft without needing to get those allegedly affected by its behaviour involved and onside first.
Over the past 12 months, Microsoft has been given the chance to respond to the claim, and – in October 2025 – Stasi issued her first call for businesses that suspect they’ve fallen foul of Microsoft’s alleged licensing practices to get in touch and join her group action.
Ahead of the 11 December CAT court date, Computer Weekly sat down with Stasi to find out what it is about Microsoft’s cloud licensing practices that persuaded her to take on this fight on behalf of the UK business community.
“Microsoft is dominant on some parts of the [IT infrastructure] stack and is using this power to impose things that otherwise will be difficult to accept for business users, and the reality is that they can do that because they limit choice for people,” she says.
“It’s not just about the [fact its services are] overpriced, it’s also about how difficult it is for users to switch and use other providers, and how that limits competition within the market.”
She adds: “[The cloud market] is a sector of the economy that should be very vibrant, innovative and open because we all rely on it, but it’s not. And someone is making a profit out of this situation, so things need to change.”
Stasi makes the point that it would be very difficult for a single business, upset with its treatment by Microsoft, to launch a legal action against the company alone and achieve that change.
“[It’s] my mission. to represent all of [the affected users] and try to get their money back, working on the theory that together, you’re a stronger force”
Maria Luisa Stasi, competition lawyer
“That’s my mission. I want to represent all of [the affected users] and try to get their money back on their behalf, working on the theory that if you unite together, you’re going to be a stronger force to be reckoned with.”
The UK court system is set up well to support this kind of claim, she says, with one of the most advanced systems in Europe for pursuing this kind of group claim. “It’s also exciting to be part of shaping this body of law that, to me, is one of the best guarantees we have for the public interest to be respected.”
Momentum for change
Citing the European Commission’s recently launched investigation into Microsoft, and the previous work done by Ofcom and the CMA to bring to light aspects of the software giant’s anti-competitive behaviours, Stasi says there is a real momentum building to get the software giant to change how it operates.
However, change will take time, she admits. “We are hoping to see some remedies introduced soon [on the back of the outcome of the CMA’s work], but it’s not a fast process, and even my proposed class action is not going to progress quickly.”
She says: “We went to court a year ago, and we’re hoping to have the certification in a couple of weeks’ time, but that doesn’t mean we’re going to get judgment anytime soon. But if we get certified [after 11 December 2025], we can start working towards the trial, and the game is on.”
Microsoft’s take on Stasi’s case
Perhaps unsurprisingly, Microsoft has not taken the news of Stasi’s legal action particularly well, with a spokesperson for the company sharing a statement with Computer Weekly that accuses Stasi of trying to opportunistically capitalise on Google Cloud’s complaint to the European Commission about Microsoft’s licensing practices.
Incidentally, Google Cloud withdrew its complaint on 28 November 2025, citing the European Commission’s decision to conduct its own investigation into Microsoft’s grip on the continent’s cloud computing market.
“This is an opportunistic attempt by a law firm and its private funders to piggy-back on baseless complaints Google has made and which we’ve all addressed or rebutted,” the Microsoft spokesperson’s statement reads.
“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.”
Stasi dismisses Microsoft’s take on her legal action and the notion that its existence owes anything to Google’s (now abortive) attempt to address its rival’s cloud licensing strategy.
“I’m grateful to my brilliant legal team and supportive funders, but the driving force for this case is me. What’s more, my voice is not alone. UK regulators found that Microsoft charges higher prices for using its software on rival cloud services,” she says. “The European Commission recently announced a similar probe into Microsoft’s cloud services.”
In response to Computer Weekly’s questions about how Microsoft has engaged with the legal process so far, she says: “It won’t surprise you that we have a completely different reading of what the impact of its actions are on the class [the businesses involved] and on those sectors of the economy overall.”
She continues: “We’re trying to do everything we can to solve all the different things that can be solved before getting to a potential trial, so that the latter can be straightforward and proceed as fast as is reasonably possible.”
I would be very surprised if nothing changes in the cloud market over the next five years. There are political discussions, policy discussions and enforcement actions coming down the line, so everything seems to be in place for a change to come Maria Luisa Stasi, competition lawyer
The trial will also be an opportunity to address what Stasi describes as an “asymmetry of information” in this case, which would not be possible without getting Microsoft into the courtroom.
“One of the aspects covered by this asymmetry of information is how many clients are actually paying what I consider to be an overcharge [to run Microsoft software in competing clouds],” she says.
“This is something I don’t know precisely, but our experts have been estimating this based on publicly accessible information. The precise number is known to Microsoft, but this type of disclosure won’t happen unless we go to trial.”
She adds: “The piece that I’m arguing is that Microsoft’s [behaviour around licensing has] a real financial impact on many, many businesses and public administrations, which needs addressing.”
With an imminent court date, the CMA’s actions set to take effect in 2026, and the European Commission’s own investigation into Microsoft now underway, Stasi says she is confident that the cloud market will become a much more level playing field in the years to come.
“I would be very, very surprised if, in five years from now, we’re sitting, having this conversation and nothing has changed,” she says.
“This class action might be one of the entry points [for change] and is particularly targeted on claiming back some extra charges, but there is a lot going on [in the cloud market] with the European Commission investigation and the CMA and the work they’re doing to restructure the market, but this is only part of the story.”
She then went on to cite the October 2025 AWS outage in the US, which had far-reaching consequences across the globe, as further evidence that having a market so reliant on just a handful of large tech firms is far from ideal.
“The outages are a strong reminder of what kind of harms and problems we can face as a democracy and as a citizenry, if we keep on having this environment so concentrated and so controlled in brackets by just a few global players,” she says.
“This makes it extremely difficult to guarantee basic principles such as observability, transparency, accountability and resilience. I would be very surprised if nothing changes in the cloud market over the next five years. There are political discussions, there are policy discussions, and there are enforcement actions coming down the line, so everything seems to be in place for a change to come.”
UK companies interested in joining Stasi’s legal action can find out more about it here: ukcloudclaim.com/register.
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