Google and Microsoft have objected to the $40bn (£29bn) takeover of British chipmaker arm by Nvidia as the deal faces an in-depth competition probe in the US.
The two tech giants, as well as semiconductor rival Qualcomm, are among the companies to object to the mammoth merger amid concerns it could harm competition.
The US Federal Trade Commission has opened an in-depth investigation, while the UK Competition and Markets Authority is reviewing the deal.
Cambridge-based Arm, which designs chips for mobile phones, licenses its technology to firms including Nvidia and Intel.
The proposed deal has sparked concerns that Nvidia could block its rivals’ access to Arm’s intellectual property.
Nvidia has said it will retain Arm’s neutral licensing model and has pledged to keep the company headquartered in the UK.
But a string of critics have hit out at the deal.
Hermann Hauser, who co-founded ARM’s predecessor Acorn Computers, which then linked up with Apple in a joint venture to spin out ARM in 1990, described the Nvidia move as a “disaster” for Britain.
The takeover was first announced in September, but Nvidia has warned it could take 18 months to complete due to the high level of regulatory scrutiny.
“As we proceed through the review process, we’re confident that both regulators and customers will see the benefits of our plan to continue Arm’s open licensing model and ensure a transparent, collaborative relationship with Arm’s licensees,” a Nvidia spokesperson said.
“Our vision for Arm will help all Arm licensees grow their businesses and expand into new markets.”