Amazon’s $4 billion investment in US artificial intelligence startup Anthropic is being investigated in the latest probe into technology collaborations by the UK Competition Authority.

The Competition and Markets Authority (CMA) said on Thursday it is launching a preliminary investigation into the deal before deciding whether to refer it for a full investigation.

The deal, announced in March, included a $4bn (£3.16bn) investment in Anthropic by Amazon and a commitment from Anthropic to use Amazon Web Services “as its primary cloud provider for mission-critical workloads, including security research and the development of future foundation models”.

The regulator said it is “considering whether it is or could be the case that Amazon’s collaboration with Anthropic has resulted in the creation of a relevant merger situation”.

An Anthropic spokesperson said: “We are an independent company. Our strategic partnerships and investor relationships do not compromise our independence from corporate governance or our freedom to collaborate with others.

“Amazon does not have a seat on Anthropic’s board of directors, nor does it have any observer rights. We intend to work with the CMA and provide them with comprehensive insight into Amazon’s investment and our commercial partnership.”

An Amazon spokesperson said: “We are disappointed that the UK CMA has not yet concluded its investigation. Amazon’s partnership with Anthropic does not raise competition concerns and does not meet the CMA’s own threshold for review.

“In the early days of generative AI, there was largely one successful option available to customers. Anthropic has worked hard to become an emerging viable alternative. But building models is expensive, and companies like Anthropic need access to a substantial amount of capital to train these models.”

Amazon said its investment would help increase competition in the emerging sector and that Anthropic was “free to partner with any other vendor (and indeed has multiple partners)”.

Last week, the CMA announced a near-identical investigation into Google’s partnership with Anthropic. It is also investigating Microsoft’s unusually structured partnerships with AI lab Inflection and OpenAI, the maker of ChatGPT.

An investigation by the CMA into a deal between Microsoft and French AI startup Mistral was dropped in May.