Top 10 firms hold nearly 38 % of S&P 500 value, valuations exceed dot‑com peak on mega‑caps

Bank of America just dropped a massive warning that U.S. growth stocks hover in a bubble bigger than the dot‑com crash. A recent note shows about 37 % of the S&P 500 is tied up in ten firms alone, near the highest level ever recorded and edging into record territory. The average P/E for those top names clocks in around 26 × compared to roughly 20 × for the rest of the index. That surpasses the dot‑com peak when P/E reached about 26.4 × by year‑end 2000. Another metric flags forward P/E close to 22.4 × overall—one of the highest in two decades.
Albert Edwards at Société Générale calls it an “everything bubble” and cites a Shiller CAPE near 38, a level last seen before major crashes.
https://www.businessinsider.com/stock-market-crash-famed-market-bear-warns-of-everything-bubble-2025-7

Lisa Shalett, Morgan Stanley Wealth Management CIO, warned “If the biggest stocks fall the most, the index is very vulnerable.”
https://www.reuters.com/business/autos-transportation/us-stock-market-concentration-risks-come-fore-megacaps-report-earnings-2025-07-23/

Passive funds now control roughly 54 % of the market and pour trillions into whatever those mega‑caps do. That feeds the illusion of safety in index investing. Heavy concentration does not equate to true diversification. Smarter money sees fragility.

Follow the money quietly. Fees flow from billions parked in index funds. Trading desks profit from sheer volume in the mega‑caps. Risk is off‑loaded onto retail investors who bought the “diversified” index. Wall Street collects on debt, deals and derivatives tied to the same narrow set of names.