对话耶鲁经济学家罗奇：美国AI泡沫风险或远超互联网泡沫

Core Viewpoint - The current surge in U.S. stock market valuations driven by artificial intelligence (AI) shows signs of significant bubble risk, despite AI's transformative potential [1][2] Group 1: AI's Potential and Market Dynamics - AI is believed to have the potential to reshape economic activities, employment structures, and intellectual capital growth, leading investors to actively position themselves for these changes [2] - The valuation increase in major U.S. indices, particularly driven by the "Magnificent Seven" companies, has become severely imbalanced, with these companies accounting for 30% to 35% of the S&P 500's market capitalization [2][3] - This concentration is notably higher than during the 2000 internet bubble, where tech stocks represented only about 6% of the S&P 500's market cap [2] Group 2: Warning Signs of a Bubble - Key characteristics of asset bubbles, such as steep price increases and concentration of overvalued stocks, are currently evident in the market [3] - Speculative behavior is increasingly observed, where investors buy based on the expectation of rising prices rather than fundamental company performance [3] Group 3: Implications for Monetary Policy - Since the 2008-2009 financial crisis, there has been heightened attention to asset prices and their relationship with monetary policy [4] - A sudden surprise from the Federal Reserve, such as not lowering interest rates when expected, could lead to significant adjustments in the overvalued U.S. stock market [4] - In the event of a sharp market decline, the Federal Reserve may need to signal its readiness to support the market, similar to actions taken during past financial crises [4]