深夜，美股开盘巨震！

Core Viewpoint - Moody's downgrade of the US sovereign rating has triggered volatility in the US financial markets, with significant fluctuations in stock indices and bond yields [1][4][6]. Group 1: Rating Downgrade - On May 16, Moody's downgraded the US government's long-term issuer and unsecured debt rating from AAA to AA1, changing the outlook from negative to stable [4]. - The downgrade reflects the rising debt and interest payment ratios of the US government over the past decade, which have exceeded those of similarly rated sovereign nations [4]. - Moody's noted that the stable outlook is based on the US's unique credit strengths, including its economic scale, resilience, and the dollar's status as a global reserve currency [4]. Group 2: Market Reactions - Following the downgrade, US stock indices experienced significant initial declines, with the Nasdaq and S&P 500 dropping over 1% at one point, while the Dow Jones fell more than 0.7% [1][8]. - By the end of the trading session, the Dow Jones, Nasdaq, and S&P 500 indices were down 0.12%, 0.61%, and 0.39%, respectively [9][10]. - US Treasury yields also rose, with the 10-year Treasury yield increasing by 7 basis points to nearly 4.55%, while the 30-year Treasury yield surpassed 5% [2][7]. Group 3: Economic Perspectives - Some analysts view the downgrade as a symbolic warning regarding US debt and deficit pressures, while others see it as a potential buying opportunity in the stock market [12]. - Morgan Stanley's chief equity strategist suggested that the correlation between stock returns and bond yields may shift, making stocks more sensitive to interest rate changes [12].