The Kobeissi Letter(@KobeissiLetter):BREAKING: The top 10 US stocks now account for 43% of the S&P 500’s market cap, near the highest on record. This percentage has been at or above 40% for the last 12 months. Over the last 10 years, the top 10's weighting in the S&P 500 has more than DOUBLED. At the same time, the proportion of the 250 smallest companies has halved, to ~7%, the lowest since at least 2014. To put this differently, the top 10 now account for more than 6 times the market cap of the smallest 250 firms in the S&P 500 index. A handful of stocks continue to effectively drive the entire market.

2026.07.09 14:01

BREAKING: The top 10 US stocks now account for 43% of the S&P 500’s market cap, near the highest on record. This percentage has been at or above 40% for the last 12 months. Over the last 10 years, the top 10's weighting in the S&P 500 has more than DOUBLED. At the same time, the proportion of the 250 smallest companies has halved, to ~7%, the lowest since at least 2014. To put this differently, the top 10 now account for more than 6 times the market cap of the smallest 250 firms in the S&P 500 index. A handful of stocks continue to effectively drive the entire market.