Semiconductor stocks led by Nvidia (NVDA) and Advanced Micro Devices (AMD) fell Wednesday on worries over tougher U.S. restrictions on artificial intelligence technology exported to China. X The Biden administration is weighing tougher restrictions on exports of computer chips that process AI software, the Wall Street Journal reported late Tuesday. The new restrictions would also apply to Nvidia's less powerful A800 AI chips, which were designed to avoid export curbs. "The U.S. Commerce Department could move as soon as July to stop shipments of chips made by NVDA and others to customers in China without first obtaining a license," Jefferies...