The S&P 500 consists of 500 companies that issue a total of 505 stocks, as some companies, such as Berkshire Hathaway, have issued multiple classes of shares. The top 10 largest holdings are listed on the official S&P Global website. However, S&P does not currently provide the total list of holdings, at least not for free. Subscribers to S&P's research unit, Capital IQ, can get access to the entire list.

Key Takeaways

  • A constituent is a member or component of a market index like the S&P 500.
  • Companies must meet certain requirement criteria, which are determined by the publishers of the index, before being added to an index.
  • The S&P 500 index is market capitalization weighted, where it gives a higher percentage allocation to companies with the largest market cap.
  • To join the S&P 500, a stock must meet a broad set of criteria, including having a total market cap of at least $11.8 billion, and with a public float of at least 10% of shares outstanding.

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S&P 500 Inclusion Criteria

The S&P 500 is one of the most widely quoted stock market indexes because it represents the largest publicly traded companies in the U.S. The S&P 500 focuses on the U.S. market's large-cap sector.

To be added to the S&P 500, a stock must meet a broad set of criteria, including a total market cap of at least $11.8 billion. Additionally, the company must be a U.S. company, have a public float of at least 10% of its shares outstanding, have a positive sum of four consecutive quarters of trailing earnings, report positive earnings for its most recent quarter, and also meet certain liquidity requirements. Companies may be removed from the S&P 500 if they deviate substantially from these standards.

$38.2 trillion

The total combined market cap of the 500 companies in the S&P 500 as of Sept. 30, 2021.

S&P 500 Calculation

The S&P 500 is a free-float market capitalization-weighted index. This means that the more valuable an individual company's stock becomes, the more it contributes to the S&P 500's overall return. It is not uncommon for three-quarters of the index's return to be linked to only 50 to 75 stocks.

Therefore, the addition or subtraction of smaller companies from the index will not have a noticeable impact on the overall return of the index. However, the removal or addition of even just one of the largest stocks can have a major impact.

S&P 500 components are weighted by free-float market capitalization. Larger companies affect the value of the index to a greater degree.

Top 25 Components by Market Cap

Because the exact weightings of the top 25 components are not available from S&P directly, the weightings below are from the SPDR S&P 500 Trust ETF (SPY). SPY is the oldest ETF that tracks the S&P 500, as well as the largest by assets under management (AUM) and the most highly traded. Moreover, SPY is the oldest and largest ETF, period. This means that its weightings should do a very good job of underlying the matching S&P 500 index, although the two may not be exactly the same. As of October 25, 2021, the following are the twenty-five largest S&P 500 index constituents by weight:

  1. Apple Inc. (AAPL): 6.03%
  2. Microsoft Corp. (MSFT): 5.98%
  3. Inc. (AMZN): 3.73%
  4. Tesla Inc. (TSLA): 2.15%
  5. Alphabet Inc. Class A (GOOGL): 2.14%
  6. Facebook Inc. Class A (FB): 2.02%
  7. Alphabet Inc. Class C (GOOG): 2.02%
  8. NVIDIA Corporation (NVDA): 1.49%
  9. Berkshire Hathaway Inc. Class B (BRK.B): 1.38%
  10. JPMorgan Chase & Co (JPM): 1.31%
  11. Johnson & Johnson (JNJ): 1.11%
  12. UnitedHealth Group Inc. (UNH): 1.09%
  13. Home Depot Inc. (HD): 1.01%
  14. Visa Inc. Class A (V): 1.01%
  15. Bank of America Corp. (BAC): 0.90%
  16. Procter & Gamble Co. (PG): 0.88%
  17. Mastercard Inc. Class A (MA): 0.81%
  18. Walt Disney Co. (DIS): 0.80%
  19. Adobe Inc. (ADBE): 0.79%
  20. Netflix Inc. (NFLX): 0.76%
  21. Paypal Holdings Inc. (PYPL): 0.74%
  22., Inc. (CRM): 0.73%
  23. Exxon Mobil Corp. (XOM): 0.70%
  24. Comcast Corp. Class A (CMCSA): 0.63%
  25. Pfizer Inc. (PFE): 0.62%