The U.S. stock market is exhibiting signs of significant overvaluation, with the S&P 500's market value now comprising 45% of the global GDP, a figure that has doubled in recent years. This level is higher than the 38% recorded at the peak of the Dot-Com bubble in 2000. The concentration of wealth among the top 10 S&P 500 stocks has reached a record 37%, surpassing the previous Dot-Com bubble peak by 10 percentage points. Additionally, the forward price-to-earnings ratio for these top stocks is approximately 30 times, exceeding the 25 times seen two decades ago. The Bank of America has indicated that the S&P 500 is considered expensive on 19 out of 20 valuation metrics, with certain measures, such as the Shiller Price to Earnings ratio, exceeding historical averages by over 100%. Market sentiment is notably high, with 51.4% of U.S. consumers expecting higher stock prices over the next year, the highest level of optimism recorded since 1987. Furthermore, U.S. households have increased their stock market exposure to a record 48%, aligning with levels seen during the Dot-Com bubble peak, indicating a strong retail investor presence in the market.