The S&P 500 is currently trading at elevated valuation levels, with multiple metrics indicating the market is expensive relative to historical norms. The Shiller price-to-earnings (P/E) ratio for the S&P 500 reached 39 times earnings, the highest level since the 2000 Dot-Com bubble burst. This ratio, which measures price relative to the average inflation-adjusted earnings over the past 10 years, is higher than 96% of historical observations. The technology sector now constitutes approximately 44% of the S&P 500's market capitalization, marking its largest share ever and a doubling since 2018. This surpasses the tech sector weight of around 35% at the peak of the 2000 bubble. Meanwhile, the forward 12-month P/E ratio stands at 22.4, exceeding both the five-year average of 19.9 and the ten-year average of 18.4. The trailing 12-month P/E ratio is 27.9, also above the five-year average of 25.0 and the ten-year average of 22.5. The equity risk premium for the S&P 500 is about 2.25%, indicating limited additional yield over the 10-year Treasury Inflation-Protected Securities (TIPS). Despite strong leadership from large-cap technology stocks in recent months, the tech sector has underperformed within the S&P SmallCap 600 index.