You Own 500 Companies. Ten of Them Are 41% of Your Portfolio.

Chart of the Day

SEPTEMBER 18, 2026

MARKETS • S&P 500

Ten Stocks Now Make Up 41% of the S&P 500. At the Dot-Com Peak It Was 27%.

That is not diversification. That is a bet on ten companies wrapped in an index fund.

19%

1990

27%

2000
PEAK

17%

2015
LOW

41%

2026
TODAY

Share of the S&P 500 market capitalization held by its ten largest companies. Today’s reading is the highest on record.

Source: RBC Wealth Management and J.P. Morgan Asset Management, 2026

You bought an S&P 500 index fund because you wanted to own America. Five hundred companies. Every sector. Every state. The safe, boring bet Warren Buffett has been telling ordinary Americans to make for forty years. Well… about that.

The top ten stocks in the S&P 500 now make up 41% of the entire index. Not 20%. Not 25%. Forty-one percent. When you put a dollar into that “diversified” fund, 41 cents goes to Apple, Microsoft, Nvidia, Amazon, Alphabet, Meta and a few of their friends. The other 490 companies fight over the remaining 59 cents.

Here is what most people miss. At the peak of the dot-com bubble in March 2000, the top ten were 27% of the index. That was the previous record. When those names cracked, the S&P lost half its value and did not fully recover for 13 years. Today we are at 41%. That is not just higher than dot-com. That is 50% more concentrated than dot-com.

Look at your 401(k) statement. If it says “US Large Cap Index” or “Total Stock Market,” you are riding this concentration. So is every pension fund. So is every state retirement system in the country. When Nvidia sneezes, your retirement account catches the flu. That was not the deal you signed up for when you bought an index fund forty years ago. But that is the deal you own today.

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THE TAKEAWAY

“Ten companies now make up 41% of the S&P 500. At the peak of the dot-com bubble in 2000, that number was 27%. We are already more concentrated than the last time this ended badly.”

The fix is not complicated. Equal-weight S&P 500 funds exist. So do dividend-focused funds. So do international funds. None of them have shot the lights out the last three years, and that is exactly the point. When one bet stops working, you want the other bets to still be running. Look at your holdings this weekend. Add up the percentage sitting in just five tech names. If the answer surprises you, that is your homework. This weekend. Not after the next earnings call.

More tomorrow. Stay sharp.

— Ray Calloway

You Own 500 Companies. Ten of Them Are 41% of Your Portfolio.

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