US President Donald Trump signed an executive order on Thursday that imposes a 15% tariff on imported products made from polysilicon, a crucial material used in semiconductors and solar panels. It comes after a national security investigation into the production of the material overseas. Trump said in the order that he had accepted recommendations by Secretary of Commerce Howard Lutnick to set minimum import prices as well as a 15% tariff on polysilicon and related imports. The order is likely to benefit Hemlock Semiconductor and Wacker Chemie, which are the main producers of the material in the US. The production of computer chips is central to the race between the US and China to develop artificial intelligence (AI).