S&P 500
IndexS&P 500 concentration (2026)
The ten biggest companies in the S&P 500 hold 37.9% of it as of Mar 2026 — up from 22.8% in Sep 2019. The top five hold 28.2%, and NVIDIA Corp alone holds 7.6%. 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 to see who held each slot and at what weight. Switch between the top 1, 3, 5 and 10.
Share of S&P 500 by index weight, as filed by the tracking fund each quarter. Bands are rank slots — the bottom band is whichever company is largest that period. Hover for names and weights.
Who is in the top ten now, and who was then#
| # | Mar 2026 | Weight | Sep 2019 | Weight |
|---|---|---|---|---|
| 1 | NVIDIA Corp | 7.58% | Microsoft Corp | 4.30% |
| 2 | Apple Inc | 6.66% | Apple Inc | 3.85% |
| 3 | Alphabet Inc | 5.39% | Alphabet Inc | 2.97% |
| 4 | Microsoft Corp | 4.91% | Amazon.com Inc | 2.92% |
| 5 | Amazon.com Inc | 3.64% | Facebook Inc | 1.73% |
| 6 | Broadcom Inc | 2.62% | Berkshire Hathaway Inc | 1.65% |
| 7 | Meta Platforms Inc | 2.24% | JPMorgan Chase & Co | 1.52% |
| 8 | Tesla Inc | 1.87% | Johnson & Johnson | 1.38% |
| 9 | Berkshire Hathaway Inc | 1.57% | Procter & Gamble Co/The | 1.26% |
| 10 | JPMorgan Chase & Co | 1.42% | Exxon Mobil Corp | 1.21% |
Into the top ten since Sep 2019: NVIDIA Corp, Broadcom Inc, Meta Platforms Inc, Tesla Inc. Out of it: Facebook Inc, 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 the S&P 500?
- The ten largest companies hold 37.9% of the index as of Mar 2026, and the largest alone (NVIDIA Corp) holds 7.6%. In Sep 2019 the top ten held 22.8%, so the index has become markedly more top-heavy over that span.
- When was S&P 500 most concentrated?
- On the filings we hold, the top ten peaked at 40.7% in Dec 2025, against 37.9% now. Our weights run from Sep 2019 onward; for a longer, market-wide view of top-heaviness see the concentration visual.
- 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; for a longer view of how top-heavy the US market as a whole has become, measured monthly from market caps since 2010, see market concentration. See also the sector mix — the other way an index can be less diversified than its member count suggests. Not investment advice.
ChartRow is not affiliated with, sponsored by, or endorsed by S&P Dow Jones Indices LLC, S&P Global, or Nasdaq, Inc. "S&P 500®" and "Dow Jones®" are registered trademarks of S&P Dow Jones Indices LLC; "Nasdaq-100®" is a registered trademark of Nasdaq, Inc. They are used here only to identify the indexes discussed. All index-related figures on this page are independently derived from public sources — SEC filings, Robert Shiller's public dataset, and our own computations — not from any index provider's data feed.