According to @KobeissiLetter on X, posted Sep 9, 2025, the combined weight of S&P 500 constituents with at least 3% share of the index has reached roughly 32%, tripling in eight years. Source: @KobeissiLetter on X, Sep 9, 2025. At the 2000 dot-com peak, this figure was below 10%, underscoring unprecedented concentration today. Source: @KobeissiLetter on X, Sep 9, 2025. Six companies now each exceed a 3% index weight, and NVDA alone represents about 8% of the S&P 500’s market value, both cited as records. Source: @KobeissiLetter on X, Sep 9, 2025. Higher index concentration increases sensitivity of the S&P 500 to single-stock earnings and guidance shocks, as documented by S&P Dow Jones Indices’ research on concentration risk. Source: S&P Dow Jones Indices, 2023 analysis on S&P 500 concentration risk. For crypto traders, elevated equity concentration matters because Bitcoin and U.S. equities have exhibited higher return correlations since 2020, implying spillover potential from mega-cap tech moves to BTC and ETH. Source: IMF Blog, Crypto Prices Move More in Sync With Stocks, Jan 11, 2022.