Amazon and Microsoft have thrown their support behind the proposed Gain AI Act, a U.S. bill that would restrict Nvidia and other chipmakers from exporting advanced semiconductors to China and other embargoed markets until domestic demand is fully met. The move marks an unusual policy rift between Nvidia and two of its biggest customers, highlighting intensifying competition for AI chips inside the United States.The legislation aims to safeguard U.S. supply for cloud providers and data-centre operators racing to build AI infrastructure. It has gained backing from Amazon, Microsoft and AI developer Anthropic, who favour a clause granting “trusted entities” export exemptions without requiring government licences, a provision that would ease their global operations and potentially give them a competitive advantage.Nvidia, which controls about 80% of the AI chip market, has mounted a heavy lobbying effort against the bill, spending US$3.5 million this year. The company argues the act risks distorting global semiconductor markets and could trigger even tighter export restrictions from Washington.The Gain AI Act has support from key Democrats including Senate Majority Leader Chuck Schumer and could be folded into the National Defense Authorization Act before year-end. But it still needs approval from Senate and House Republicans, and faces scepticism from some White House officials. Supporters maintain the bill is essential to preventing future chip shortages and reinforcing U.S. leadership in AI. This article was written by Eamonn Sheridan at investinglive.com.