US Stock Market concentration (2026)
The ten biggest companies in US Stock Market hold 33.3% of it as of Jun 2026 — up from 18.8% in Sep 2019. The top five hold 24.3%, and NVIDIA Corp alone holds 6.3%. Weights are the index's own, from the tracking fund's quarterly SEC filings, so they reconcile with the constituents list.
Share of the index held by its largest members#
Each band is a rank slot, not a fixed company — band 1 is whoever is biggest in that filing. Hover a band to see who holds that slot today; switch between the top 1, 3, 5 and 10.
Share of US Stock Market by index weight, as filed by the tracking fund each quarter.
Who is in the top ten now, and who was then#
| # | Jun 2026 | Weight | Sep 2019 | Weight |
|---|---|---|---|---|
| 1 | NVIDIA Corp | 6.36% | Microsoft Corp | 3.60% |
| 2 | Apple Inc | 5.87% | Apple Inc | 3.09% |
| 3 | Alphabet Inc | 5.18% | Amazon.com Inc | 2.47% |
| 4 | Microsoft Corp | 3.83% | Alphabet Inc | 2.46% |
| 5 | Amazon.com Inc | 3.19% | Facebook Inc. | 1.45% |
| 6 | Broadcom Inc | 2.47% | Berkshire Hathaway Inc | 1.38% |
| 7 | Micron Technology Inc | 1.80% | JPMorgan Chase & Co | 1.21% |
| 8 | Meta Platforms Inc | 1.71% | Johnson & Johnson | 1.16% |
| 9 | Tesla Inc | 1.64% | Procter & Gamble Co/The | 1.06% |
| 10 | Eli Lilly & Co | 1.40% | Exxon Mobil Corp | 1.01% |
Into the top ten since Sep 2019: NVIDIA Corp, Broadcom Inc, Micron Technology Inc, Meta Platforms Inc, Tesla Inc, Eli Lilly & Co. Out of it: Facebook Inc., Berkshire Hathaway Inc, JPMorgan Chase & Co, Johnson & Johnson, Procter & Gamble Co/The, Exxon Mobil Corp. The largest member has changed too — Microsoft Corp then, NVIDIA Corp now. Arrivals and departures are matched by ticker, so a company that renamed or re-listed in between (Facebook to Meta) can show up on both lists.
FAQ#
- How concentrated is US Stock Market?
- The ten largest companies hold 33.3% of the index as of Jun 2026, and the largest alone (NVIDIA Corp) holds 6.3%. In Sep 2019 the top ten held 18.8%, so the index has become markedly more top-heavy over that span.
- When was US Stock Market most concentrated?
- On the filings we hold, the top ten peaked at 36.0% in Dec 2025, against 33.3% now. Our weights run from Sep 2019 onward.
- Does concentration make the index riskier?
- It makes it less diversified than the member count suggests: when ten names are a third of the index, the index's return is largely their return, and a sector shock that hits them hits everything. It is not a market-timing signal — concentration has risen for long stretches while the index compounded — but it does mean a cap-weighted position is a much more concentrated bet than "500 companies" sounds.
Weights are as filed by the tracking fund on Form N-PORT each quarter — the index's own weights, not a market-cap approximation — and a company's share classes are combined into one row, so “top ten” means ten companies. Our filings begin Sep 2019. See also the sector mix — the other way an index can be less diversified than its member count suggests. Not investment advice.
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More on US Stock Market
- Companies & weights3477
- Stock performance3477
- Sector weights36.6%
- Return calculator$1,679
- Dividend yield1.00%
- Buyback yield1.49%
- Shareholder yield2.49%
- Earnings$2.72T