Regulators in the United States have moved to block Nvidia’s $80 billion takeover of Arm, the British microchip designer.
The U.S. Federal Trade Commission launched the legal challenge on Thursday against Nvidia, one of the world's largest chip companies.
It says the proposed deal would give the U.S. company control over computing technology and designs that competitors rely on to create their own chips.
The concerns raised echo those of British and EU regulators, who have also been scrutinising the proposed takeover.
Arm licenses its blueprints to major chipmakers such as Apple, Qualcomm and Samsung Electronics, underpinning the global smartphone ecosystem.
The FTC alleges that the merger would ultimately result in 'reduced product quality, reduced innovation, higher prices, and less choice, harming the millions of Americans who benefit from Arm-based products.'
Nvidia said it would work to demonstrate that the transaction would benefit the industry and promote competition.
Arm declined to comment.
Nvidia agreed to buy Arm from SoftBank, the Japanese technology conglomerate, in September last year.