Elon Musk has joined a chorus of tech industry opposition to the $40bn (£29bn) takeover of the British chip designer Arm by a US rival.

The billionaire’s electric car pioneer Tesla has signalled competition concerns over Nvidia’s buy-out of the Cambridge semiconductor company, multiple sources said.

The US monopolies watchdog, the Federal Trade Commission, launched an inquiry into the deal earlier this year and its findings are expected in the coming weeks. The Sunday Telegraph also understands that e-commerce giant Amazon and smartphone maker Samsung have lodged opposition to the deal with US authorities.

Amazon and Samsung declined to comment. Tesla did not respond to requests for comment.

Nvidia’s takeover of Arm is facing a lengthy competition investigation in the UK. The Competition and Markets Authority this month warned the deal posed “significant” concerns.

Arm, which was acquired by Japan’s SoftBank in 2016, licenses microchip technology that is used as the blueprint for billions of smartphone processors and is viewed as a key strategic player in the chip sector.

Arm/Nvidia timeline (new)

Critics of the deal argue it would combine Nvidia’s leading supply of graphics chips with the Cambridge’s firm’s mobile products. The pair would also dominate the supply of data centre chip designs.

They fear the takeover would break Arm’s reputation for “neutrality” and lead to price rises. Nvidia has rejected these claims and said it is prepared to maintain Arm’s independence.

But the deal has sparked criticism from customers. At its recent results, Nvidia said: “Some Arm licensees have expressed concerns or objected to the transaction.”

Nvidia is awaiting a decision from Oliver Dowden, Secretary of State for Digital, who is due to report on whether the deal poses concerns for national security. Nvidia declined to comment.