Shares in computer chipmakers slumped on Wednesday after Nvidia said tighter US government controls on exports of computer chips used for artificial intelligence will cost it an extra 5. 5 billion dollars (£4. 15 billion).

Nvidia on Wednesday reported a surge in fourth-quarter profit and sales as demand for its specialised Blackwell chips, which power artificial intelligence (AI)  systems, continued to grow, sending the company’s stock higher after hours.

The US Supreme Court is allowing a class-action lawsuit that accuses Nvidia of misleading investors about its past dependence on selling computer chips for the mining of volatile cryptocurrency to proceed.

Now more valuable than Microsoft, having also overtaken fellow tech giant Apple earlier this month

US computer chip maker Nvidia has become the world’s most valuable company after its share price reached an all-time high on Tuesday.

Graphics chip maker Nvidia has said it plans to build Britain’s fastest supercomputer that healthcare researchers can use to work on medical problems including Covid-19.