估值达到科网泡沫以来新高，美国科技股扛得住吗？

Core Insights - The TMT sector in the U.S. is showing warning signs similar to the 2000 dot-com bubble, with high valuations, market concentration, and rising internal correlations [1][10] Valuation and Growth Expectations - The TMT sector's forward P/E ratio has reached 26.7, the highest since 2009, significantly above the historical average [1][2] - Excluding the "Tech Seven," the remaining companies in the TMT sector show even more severe signs of valuation bubble, with a P/E ratio nearing 24.4, which is 11.7 standard deviations above the 2015-2019 average [2] - The TMT sector's earnings growth has outperformed the S&P 500 since Q3 2023, with expectations of an 11.8% growth rate by H2 2025, which is 1.8 times the overall index growth [5] Market Concentration - The TMT sector accounts for 44.2% of the S&P 500's total market capitalization, approaching the historical peak of 44.7% from February 2000 [1][6] - The sector's market share has increased from 33.8% pre-pandemic, indicating a significant rise in concentration risk [6][8] Internal Correlation and Market Pressure - The internal correlation among TMT stocks has risen, often seen as a precursor to market corrections, currently averaging 0.49, well above the long-term average since 2010 [10][11] - Historical data suggests that previous peaks in correlation have led to market adjustments approximately six months later, indicating potential pressure on the sector in early 2025 [11]