Both Google and Amazon have slammed their competitor Microsoft for locking customers into its Azure cloud ecosystem, telling the UK’s competition watchdog that the way Microsoft licenses its software leaves users with “no economically reasonable alternative” than to stay with Azure.

The UK Competition and Markets Authority is currently inquiring into the cloud service market after suspecting that some major players operate in a way that “may create barriers to switching and multi-cloud”.

In its response to the UK regulator’s issues statement, Amazon and Google have gone on the offensive by pointing the blame squarely at Microsoft.

Amazon said that changes in Microsoft’s licencing agreements had made it “more difficult for customers to run some of its popular software offerings on Google Cloud, AWS, and Alibaba”.

“To use many of Microsoft’s software products with these other cloud services providers, a customer must purchase a separate license even if they already own the software,” Amazon said in its submission [PDF].

“This often makes it financially unviable for a customer to choose a provider other than Microsoft.”

Indeed, back in 2019 Microsoft announced that on-premise licences would no longer be usable for hosted cloud services, citing how the rise of big cloud providers had “blurred the line between traditional outsourcing and cloud services”.

Smaller cloud providers took Microsoft to the European Commission over this licence change which led to Microsoft updating the terms of its Services Provider License Agreement (SPLA) in 2022 to allow for on-premise licences to be used by cloud providers so long as they weren’t its major cloud competitors: Alibaba, Amazon, and Google.

That led to another antitrust complaint in Europe, this time from the Cloud Infrastructure Services Providers in Europe (CISPE) industry group, which is supported by Amazon.

Google’s submission to the UK competition watchdog contains five full pages of complaints about how Microsoft has been using its position as the default legacy enterprise software option to muscle its way toward a greater share of the accelerating cloud market.

“Over the past 30 years, Microsoft has created an ecosystem of business software solutions that includes several traditionally ‘must-have’ products for enterprise customers—namely, Windows Server, Windows Desktop, and its Office suite of products,” Google said.

“Given the ubiquity of Microsoft’s enterprise software in legacy IT stacks, it is highly unusual for a traditional enterprise customer to have no Microsoft footprint at all, and as Microsoft customers migrate from on-premises computing to the cloud, they continue to rely on Microsoft’s software products.”

By making it harder for customers to license Microsoft products on the likes of AWS and Google, the argument goes, the more Microsoft extends its already strong position in the enterprise space.

Little of this would be news for the Competition and Markets Authority, given that it directly states Microsoft as being a pre-existing source of complaints in its issues paper.

What Google does offer is a set of remedies in a way that is much more prescriptive than Amazon.

It wants to see the regulator force Microsoft to let businesses port their licenses to other cloud providers, reverse its decision to restrict the SPLA license, and open up 'must-have' tools like Active Directory.

Microsoft told the UK markets regulator that the cloud market is competitive and there was nothing for it to worry about.

“Microsoft’s view is that these hyperscalers [Amazon, Google and the like] already have the resources and capabilities to compete in the cloud services market and require no further regulatory intervention from the CMA (or other competition authorities),” Microsoft said in its submission.