Amazon has criticized Microsoft’s business practices in a letter to the United Kingdom’s (UK) competition authority.

The online retailer claimed its rival used tactics to “restrict customer choice” in a 17-page letter to the country’s Competition and Markets Authority (CMA), which investigates unfair trading practices.

The CMA launched an investigation into the supply of public cloud infrastructure services in October after telecoms watchdog Ofcom flagged the dominance of Amazon and Microsoft.

In a lengthy response to the investigation, Amazon’s legal team defended its subsidiary Amazon Web Service (AWS), the world’s most popular cloud storage platform. The American tech giant then turned its sights on fierce competitor Microsoft.

“Some IT providers, such as Microsoft, use licensing practices that restrict customer choice and make switching more difficult,” Amazon said in their letter. They highlighted how Microsoft changed its licensing terms in 2019 and again in 2022 making it “more difficult for customers to run some of its popular software offerings on Google Cloud, AWS, and Alibaba.”

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

Microsoft, Google and Amazon compete for bigger share of cloud computing market

Last week, Reuters reported how another Silicon Valley behemoth, Google,  had submitted a similar letter to the watchdog, claiming Microsoft’s business practices had left its rivals at an unfair disadvantage.

Google made six recommendations to the CMA, including forcing Microsoft to improve interoperability for customers using its Azure service and alongside other cloud programs and banning it from withholding security updates from those that switch.

In its submission to the CMA, Microsoft said the UK’s cloud computing sector was “functioning well”.

In their defense they wrote: “Microsoft firmly believes that the cloud services market is functioning well – both globally, and for UK customers. Intense competition between the long-time global leader, Amazon Web Services, and a group of rivals including Microsoft, Google, Oracle, Alibaba, IBM and others, has led to multi-billion dollar investments in infrastructure and innovation that benefit customers in the UK and around the world.

“Sustained investment by this cohort of established competitors has resulted in an ever-improving range and quality of cloud services available to UK customers, at prices which are declining over time.”

The CMA is not scheduled to make a final decision on the matter until Spring 2025.

Featured image: Pexels

Sam Shedden

Managing Editor

Sam Shedden is an experienced journalist and editor with over a decade of experience in online news. A seasoned technology writer and content strategist, he has contributed to many UK regional and national publications including The Scotsman,,, Edinburgh Evening News, The Daily Record and more. Sam has written and edited content for audiences whose interests include media, technology, AI, start-ups and innovation. He's also produced and set-up email newsletters in numerous specialist topics in previous roles and his work on newsletters saw him nominated as Newsletter Hero Of The Year at the UK's Publisher Newsletter Awards 2023. He has worked in roles focused on growing reader revenue and loyalty at one of the UK's leading news publishers, National World plc growing quality, profitable news sites. He has given industry talks and presentations sharing his experience growing digital audiences to international audiences. Now a Managing Editor at, Sam is involved in all aspects of the site's news operation including commissioning, fact-checking, editing and content planning.