Stock market concentration today
How much of the market a few companies hold, and how the typical stock keeps up.
Close of Friday 6 November 2026 · updated every trading dayWe compare each figure with every month since 2006. The usual range holds the middle 40% of those months. The marks show the value 1 month, 1 year and 5 years ago.
Top-10 concentrationWhat this measures: the market value of the 10 largest companies as a share of the value of the 500 largest US companies.
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
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Last 10 yearsEach point is one month. The dot is today.
Equal against value weightWhat this measures: the 1-year return of the 500 with equal weights minus their return weighted by market value, in points.
How well does the typical stock keep up with the largest?
Better than usual
High · higher than in 8 of 10 months since 2006
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Last 10 yearsEach point is one month. The dot is today.