深夜！全线大跌，发生了什么？

Core Viewpoint - The US stock market, particularly large technology stocks, is experiencing a significant sell-off, driven by concerns over high valuations and negative economic signals, including warnings about the impact of a government shutdown on GDP growth [2][4]. Group 1: Market Performance - Major US stock indices opened lower, with the Nasdaq down 1.3%, S&P 500 down 0.76%, and Dow Jones down 0.47% [3]. - Large tech stocks such as Nvidia, Tesla, Oracle, and AMD fell over 3%, while semiconductor stocks also faced declines, with the Philadelphia Semiconductor Index dropping over 2% [3]. - The cryptocurrency market is also under pressure, with Bitcoin dropping over 2% and Ethereum down nearly 4%, leading to significant liquidations totaling $710 million in the last 24 hours [3]. Group 2: Economic Concerns - The US government shutdown has led to the absence of key economic data, including the October non-farm payroll report, raising concerns about the Federal Reserve's decision-making for interest rates [4]. - The shutdown is expected to have a more severe impact on the economy than previously anticipated, particularly affecting the tourism and leisure sectors [4]. - Analysts suggest that once the government reopens and tariff issues are resolved, there may still be hope for a year-end market rebound [4]. Group 3: Federal Reserve Actions - Federal Reserve officials, including New York Fed President Williams, indicated that the Fed may soon need to purchase bonds to expand its balance sheet to meet liquidity demands in the financial system [5][6]. - Williams emphasized that any future bond purchases would be for liquidity management and not indicative of a new round of quantitative easing [6]. - The Fed's recent decision to end its balance sheet reduction program is seen as a response to rising market interest rates and liquidity pressures [5].