美股惊魂一周，纳指创4月来最大三周跌幅，华尔街现在很焦虑

Market Overview - Concerns over the AI bubble, expectations of economic slowdown, and profit-taking pressures have led to significant volatility in the U.S. stock market, with the S&P 500 index dropping nearly 2% this week and a cumulative decline of 3.5% since November [1] - The Nasdaq Composite index, heavily weighted in tech stocks, has fallen over 6% in November, marking its largest three-week drop since April [1] Performance of Momentum Stocks - Momentum stocks have faced severe declines, with Robinhood's market value evaporating by approximately 25% this month, Coinbase's stock plummeting by 30%, and Palantir down about 23% [3] - Goldman Sachs' basket of high-beta momentum stocks has dropped nearly 15% from its recent peak, representing the worst week for momentum performance since November 2022 [3][5] AI Sector and Nvidia's Earnings - Investors are particularly anxious about companies heavily invested in AI, with the Global X Artificial Intelligence & Technology ETF down about 10% this month, and an ETF tracking the "Big Seven" tech companies declining approximately 6.6% since the end of October [5] - Nvidia's earnings report initially led to a surge in stock price, rising 5% to $196, but then reversed sharply, closing down nearly 3% at $180.98, marking a 7% intraday drop and the lowest closing price since October 22 [5][6] Private Credit and Cryptocurrency Market - The private credit market is gaining attention from stock market investors, with concerns arising from the sudden collapse of First Brands, highlighting the risks associated with loose credit conditions [8] - The cryptocurrency market continues to exert pressure on investors, with Bitcoin's price dropping to $80,553, over 30% down from its historical high of $126,000 in early October [8][10] Market Volatility Factors - The recent volatility is attributed to high leverage and year-end profit-taking, with brokerage account financing reaching a historic high of $1.1 trillion by the end of October [11] - Leveraged market participants are facing forced liquidations in cryptocurrency positions, leading to sell-offs in tech stocks [11] - Despite the volatility, some analysts believe the market remains relatively calm, with the S&P 500 index only 4.2% below its all-time high, and many investors are still observing the market [11]