US stocks tumbled Friday. President Trump threatened a "massive increase" in tariffs on Chinese goods. The Dow fell 1.05%, the S&P 500 dropped 0.8%, and Nasdaq slid nearly 2%. The move came after China tightened export controls on rare earth minerals. Tech and China-linked stocks led losses. Rare earth stocks surged. Consumer sentiment remains weak amid the US government shutdown. The market faces uncertainty ahead of next week’s earnings season.