Nvidia, AMD fall on 15% US levy on China chip sales

** Shares of Nvidia NVDA.O down 1.8%, Advanced Micro Devices AMD.O decline 3.3% premarket

** Both chipmakers to pay 15% of China chip sale revenues to the U.S. government, official says

** Trump's administration halted sales of Nvidia's H20 chips to China in April, then allowed resumption last month

** A charge like this, if enacted, would probably raise a few billion dollars for the U.S. government, and potentially impact the gross margin of these parts by perhaps 5-15 pp, depending on the accounting - Bernstein

** YTD, NVDA rises 36%, AMD surges 43%