穆迪下调美国AAA评级，但这次和2011年大不相同了

Core Viewpoint - The recent downgrade of the US credit rating by Moody's is expected to have minimal impact on the bond market, similar to the situation in 2011 when S&P downgraded the US rating, which led to significant market turmoil at that time [1][3][9]. Group 1: Historical Context - In August 2011, S&P downgraded the US from AAA to AA+, causing panic in the market, particularly in the bond market, where the 10-year Treasury yield rose by 16 basis points on the downgrade day [2][4]. - The panic in 2011 was driven by concerns that US Treasuries might no longer qualify as eligible collateral due to the downgrade, forcing many institutions to sell off their holdings [2][4]. Group 2: Changes in Market Dynamics - After 2011, contracts were rewritten to classify securities as "government securities," removing specific credit rating requirements, which means that rating changes no longer trigger forced selling or other drastic measures [1][9]. - The downgrade by Fitch in August 2023 to AA+ had almost no effect on the bond market, as the US was already considered a split-rated AA+ country prior to Moody's downgrade [3][4]. Group 3: Market Reactions - Following the 2011 downgrade, despite initial sell-offs, the 10-year Treasury yield fell significantly by 56 basis points within a month, driven by safe-haven demand and expectations of further monetary easing by the Federal Reserve [7]. - The current market environment is different, as the systemic issues that caused turmoil in 2011 are no longer present, leading to a lack of significant impact from the recent downgrade [8][9].