September has always been a month of poor performance for the US stock market, a phenomenon known as the "September curse". The US stock market is cautious in its performance and predicts that the market may be affected by multiple factors such as the economy, politics and corporate performance.

1. US stock market performance: Since the Japanese stock market crash in early August, the US S&P 500 index has fallen from a high of 5669 in July to a low of 5119, a drop of 10%. Although it rebounded later, the upward momentum disappeared in late August and turned to sideways fluctuations.

2. Nvidia's market value evaporated: Nvidia's stock price continued to be weak after the announcement of its performance, and its market value evaporated by $300 billion overnight.

3. Historical statistics: In the 96 years since 1928, September is the only month in which the S&P 500 index has an average negative decline, with an average decline of 1.2%. Several major market declines in history, such as the bursting of the dot-com bubble in 2000 and the financial crisis in 2008, all occurred in September.

4. Reasons for the September curse: stock market expectations, macro factors (especially the Fed's interest rate policy), and psychological factors. These factors lead investors to tend to sell stocks in September.

5. Current market conditions: The current US stock market faces three major unfavorable factors: concerns about economic recession, political uncertainty in the US election, and the performance and prospects of technology stocks, especially companies such as Nvidia.

6. Future outlook: Although there may be market fluctuations in September, a sharp decline is unlikely. Investors may remain cautious, and the market may continue to move sideways or fall slightly.

7. Federal Reserve interest rate meeting: The upcoming Federal Reserve interest rate meeting will be the focus of market attention, and the results of the meeting will have an important impact on the direction of the market.