9月季节性效应逼近，美股在高位的动力恐遭截胡？

Core Viewpoint - The U.S. stock market, particularly technology stocks, has faced significant pressure, with the Nasdaq 100 index experiencing its largest drop since August 1, highlighting the vulnerability of the market supported by large-cap stocks [1][3]. Group 1: Market Performance - The Nasdaq 100 index fell by 1.4%, marking its largest decline since August 1 and the second-largest since the tariff impacts in April, with Nvidia's stock dropping 3.5% [1]. - The Nasdaq 100 index has retraced after a 40% surge since April, with high valuations contributing to the recent sell-off, as indicated by a price-to-earnings ratio of 27 times expected profits for the next 12 months [3]. - Historically, September is known for poor stock market performance, with the S&P 500 index only achieving positive returns 44% of the time since 1928, averaging a return of -1.2% [4]. Group 2: Seasonal Factors - Several factors contribute to the typical decline in September, including portfolio rebalancing by investors, behavioral finance effects, seasonal liquidity constraints, and uncertainties surrounding economic data and policies [7]. - The expectation of a market downturn in September can lead to a self-fulfilling prophecy, where investors sell off stocks in anticipation of declines, further exacerbating market volatility [7][9]. Group 3: Future Outlook - The performance of the U.S. stock market in September will depend on various factors, including tariff policies, expectations regarding Federal Reserve actions, and upcoming economic data [9]. - Historical trends suggest that when the stock market performs poorly in September, it often approaches or is at a bottom, presenting a potential buying opportunity for investors [11].