Back in the ’70s, 50 stocks accounted for about 45% of the S&P 500’s value. Today, the top 10 companies make up 40% of the index.
Markets Bloomberg May 17, 2026
The AI Stock Boom Is Starting to Feel Nostalgic
Back in the ’70s, 50 stocks accounted for about 45% of the S&P 500’s value. Today, the top 10 companies make up 40% of the index.
