英伟达盘后大跳水！特朗普，最新签署！

Group 1 - The U.S. stock market opened high but closed slightly lower on April 15, with major indices experiencing minor declines [1] - Nvidia's stock fell over 6% after the company reported a quarterly expenditure of approximately $5.5 billion related to exporting H20 graphics processors, following a requirement from the U.S. government for export licenses to certain countries and regions [1] - The Nasdaq Golden Dragon Index, which tracks Chinese stocks, declined by 0.49%, with notable individual stock movements including Alibaba down 1.48%, JD down 1.94%, and NIO up 0.28% [1] Group 2 - The White House announced an investigation into national security risks associated with the U.S. reliance on imported critical minerals and their derivatives [1] - The Canadian federal government announced the removal of certain countermeasures against U.S. imported cars to support domestic automotive manufacturers, contingent on their continued production and investment in Canada [1] - Canadian Prime Minister Carney previously announced a series of countermeasures, including a 25% tariff on U.S. imported cars not covered by the USMCA, while automotive parts remain unaffected [1]