Stats › Concentration and breadth › S&P 500 facts
The S&P 500 holds 503 constituents, not 500
| Measure | Figure |
|---|---|
| Constituents in the index | 503 |
| Separate companies | about 500 |
| Total market capitalisation | $64.51 trillion |
| Top ten weight, by company | 38.5% |
| Top ten weight, by ticker | about 37.75% |
| Largest single holding | NVDA, 7.16% |
The two top ten figures are the same measure computed two defensible ways, which is why correct sources disagree. Sources: S&P Dow Jones Indices factsheet, 30 April 2026, and Slickcharts, late July 2026.
The S&P 500 is not the five hundred largest American companies. It holds 503 constituents, because several companies have two share classes, and membership is decided by a committee applying an earnings test. Passive describes how you hold it, not how the list is made.
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