“大空头”点燃估值忧虑，纳指跌超2%，中概股难逃市场拖累

Market Overview - The S&P 500 index fell by 1.17% to 6771.55 points, the Nasdaq Composite dropped by 2.04% to 23348.64 points, and the Dow Jones Industrial Average decreased by 0.53% to 47085.24 points, reflecting concerns over high valuations in the U.S. stock market [1] Company Performance - Palantir, a leading AI stock, reported earnings that exceeded expectations and raised its guidance, yet its stock fell by 7.94%, highlighting its status as a representative of the "AI bubble" after a fourfold increase in the past year [2] - Nvidia's stock declined by 3.96%, while other major tech stocks like Apple and Microsoft saw mixed results, with Apple rising by 0.37% and Microsoft falling by 0.52% [8] - Chinese stocks also faced pressure, with the Nasdaq Golden Dragon China Index dropping by 2.05%, including Alibaba down by 2.02% and JD down by 2.93% [8] Economic Indicators - Goldman Sachs and Morgan Stanley executives expressed concerns about a potential 10% to 20% market pullback over the next 12 to 24 months, which has contributed to investor anxiety [6] - The retail investor sentiment index compiled by Goldman Sachs fell by 3.6%, indicating a significant drop in retail investor confidence [5] IPO and M&A Activity - Beta Technologies, an electric aircraft company, completed its IPO at $34 per share, raising over $1 billion, and saw its stock rise by 5.88% despite the overall market downturn [16] - Pfizer and Novo Nordisk are in a bidding war for Metsera, with Pfizer raising its offer to $8.1 billion and Novo Nordisk offering up to $10 billion, leading to a 20.5% increase in Metsera's stock [12] Corporate Developments - IBM announced plans to lay off thousands of employees in Q4, affecting a low single-digit percentage of its global workforce [15] - Amazon has issued a cease-and-desist order to AI startup Perplexity, demanding it stop using its AI browser for shopping on Amazon's platform [10] - Apple is reportedly preparing to enter the low-cost laptop market to attract consumers currently using Chromebooks and entry-level Windows laptops [11]