The UK's Competition and Markets Authority (CMA) is opening a six-month-long investigation into Nvidia's planned acquisition of Arm.

In a release, Digital Secretary Nadine Dorries has instructed the CMA to look into the deal after an initial investigation found that the union could result in “substantial lessening of competition across four key markets” – data centres, internet of things, cars and video games.

"I have carefully considered the Competition and Market Authority’s ‘Phase One’ report into Nvidia's proposed takeover of Arm and have decided to ask them to undertake a further in-depth ‘Phase Two’ investigation," Dorries wrote.

"Arm has a unique place in the global technology supply chain and we must make sure the implications of this transaction are fully considered. The CMA will now report to me on competition and national security grounds and provide advice on the next steps.

"The government’s commitment to our thriving tech sector is unwavering and we welcome foreign investment, but it is right that we fully consider the implications of this transaction."

Nvidia announced its plans to acquire Arm for $40 billion in September 2020. The CMA is one of many international competition entities to look into the deal; the UK's Department of Digital, Media, Culture and Sport intervened in the deal back in April citing national security concerns, while regulators in the US and China are also investigating the acquisition.