纳指日内暴跌5%！4月以来最惨烈波动，美股怎么了？

Core Viewpoint - The article discusses the significant decline in the U.S. stock market, particularly focusing on Nvidia's performance and the broader implications of various economic indicators and market sentiments on investor behavior [1][3][10]. Group 1: Market Performance - Nvidia's stock initially rose by 2.4% but closed down 3.2%, erasing nearly $400 billion in market value, highlighting investor concerns about the sustainability of AI chip spending despite strong revenue forecasts [1][8]. - The Nasdaq 100 index experienced a nearly 5% drop from its intraday high, closing down 2.4%, marking a 7.9% pullback from its record high on October 29 [2]. - The S&P 500 index saw a 1.9% increase in the morning but ended the day down 1.6%, with the market capitalization evaporating by over $2.7 trillion [4]. Group 2: Economic Indicators - Strong non-farm payroll data from September is seen as a signal that the Federal Reserve may end its rate cuts this year, contributing to market volatility [10][13]. - The VIX index, which measures market volatility, closed above 26 points for the first time since April, indicating increased market uncertainty [6][15]. Group 3: Investor Sentiment and Concerns - Investors are increasingly worried about whether AI investments will generate sufficient revenue or profits to justify the substantial expenditures, leading to a risk-off sentiment in the market [10][14]. - Concerns about high valuations and the potential for further losses have prompted investors to seek hedges, reflecting a protective stance in the current market environment [14][16]. - The decline in high-risk assets was particularly pronounced, with indices tracking unprofitable tech companies and heavily shorted stocks experiencing significant drops [14].