【环球财经】美股再次大跌，发生了什么？

Core Points - The US stock market experienced significant declines due to uncertainties surrounding government tariff policies, with the S&P 500 index dropping 2.71%, marking its largest single-day decline since April [1] - Analysts indicate that the market's reaction reflects both policy impacts and a recent trend of investor optimism, which may be unwarranted given the recent market performance [1] - Concerns are rising regarding whether the substantial investments in AI by companies will yield proportional returns, leading to fears that the tech-driven market rally may be nearing a critical point [2] Market Performance - The S&P 500 index closed at 6552.51 points, with a cumulative decline of 2.43% for the week, while the Nasdaq Composite index fell 3.56% to 22204.43 points, also reflecting a cumulative weekly drop of 2.53% [1] - The Dow Jones Industrial Average decreased by 1.9%, ending at 45479.6 points, with a total weekly decline of 2.73% [1] - The VIX, a measure of market volatility, rose by 31.65% to 21.63 points, indicating increased investor fear, with a cumulative increase of 29.91% for the week [1] AI Investment Concerns - Despite expectations of improved corporate revenues driven by AI, doubts are growing about the value of the massive investments in AI technology [2] - The upcoming earnings season, starting with major banks like JPMorgan, is expected to provide insights into whether the market is in a bubble, with the projected year-over-year profit growth for S&P 500 companies at 7.2%, the slowest in eight quarters [2] - Companies are facing pressure to monetize their AI investments, as many are currently incurring costs rather than generating revenue from these technologies [2]