How much do the 10 largest companies hold?
The share of the 500 largest US companies that rides on 10 of them.
Close of Friday 6 November 2026 · updated every trading day
Where is it now?
How much of the market do the 10 largest companies hold?
Far more than usual
High · higher than in 9 of 10 months since 2006
What is it?
Top-10 concentration is the share of the total value of the 500 largest US companies that the 10 largest hold. A high share means that a few companies move much of the market.
How we measure it
We add up the market value of the 500 largest US companies. Then we show how much of that total the 10 largest hold. A company with two share classes counts once.
Why it is high now
AI-writtenWritten for the close of Wednesday 4 November 2026AI writes this text each trading day from our own figures for this page. We check every number against those figures before we show the text. It gives facts only. It is not advice.
The 10 largest companies hold 38.9% of the total value of the 500, a High level. Out of every $100, about $39 sits in these 10. Apple has the biggest share at 7.1%, followed by NVIDIA and Microsoft.
What changed?
AI-writtenWritten for the close of Wednesday 4 November 2026AI writes this text each trading day from our own figures for this page. We check every number against those figures before we show the text. It gives facts only. It is not advice.
Concentration rose from 38.6% a month ago, but it is down 1.5 points from 40.4% a year ago.
HistoryEach point is one month. The dot is today. Labels mark well-known moments in the market.
The share of the 10 largest since 2006
Share of the 500 largest
The top-10 race
What does it mean for a long-term investor?
AI-writtenWritten for the close of Wednesday 4 November 2026AI writes this text each trading day from our own figures for this page. We check every number against those figures before we show the text. It gives facts only. It is not advice.
High concentration means a few companies move the index a lot. It shows how value is split, not how companies are valued. The median since 2006 is 22.3%. One measure alone does not time the market.
What does it not tell you?
Concentration does not tell you if the largest companies are priced too high or too low. It does not show when the share goes down. The largest companies can stay large for many years.