The S&P 500 is the most widely followed benchmark for the U.S. stock market. Its long-run record is genuinely useful for understanding what diversified equity investing has delivered — but it must be presented honestly: the average hides enormous year-to-year swings, and history is not a promise about tomorrow.

The Long-Run Average (Real, Cited Data)

  • •**Nominal total return (price + dividends reinvested) since 1928: about 10% per year on average.** Specific published figures include 9.98% CAGR since 1928 (Motley Fool, citing S&P Dow Jones Indices data) and 10.09% per year from 1928 through Q3 2026 (Investopedia).
  • •**Real (inflation-adjusted) return: about 6.8%–7% per year** over the long run, after subtracting historical inflation.
  • •The index is overseen by S&P Dow Jones Indices, a division of S&P Global. Annual total-return data is compiled independently by sources such as New York University Stern School of Business.

Year-to-Year Volatility Is the Catch

The ~10% average is an average of very different years. Using NYU Stern total-return data (dividends included):

  • •**2008:** about −37%
  • •**2009:** about +26%
  • •**2022:** about −18.1%
  • •**2023:** about +26.3%
  • •Over any single year the index has ranged from gains above +35% to losses near −37% in modern history.

This is exactly why a long horizon matters: the longer you stay invested, the more the good years outweigh the bad. But it also means any single-year or short-window result is essentially unpredictable.

How to Use This Honestly in Planning

  1. Use the long-run average only as a planning assumption, never as a prediction.
  2. Many planners model a conservative 6%–7% real (after-inflation) return for diversified equities over long horizons, which matches the historical real figure.
  3. Stress-test your plan with a lower return (e.g., 4%–5% real) to see whether you still reach your goal.
  4. Keep a cash emergency fund so you are never forced to sell during a down year.
  5. Model scenarios with our investment calculator using assumptions you choose.

The Critical Disclaimer

Past performance does not guarantee future results. The S&P 500 could return far more or far less than 10% in any future year or decade. Nothing on this page is a recommendation to buy or sell any security, and no future return is being predicted. For personal decisions, consult a qualified, licensed financial advisor.

<strong>Disclaimer:</strong> The content provided on CompoundFig is for educational and informational purposes only and does not constitute financial, tax, legal, or investment advice. All calculations and projections are hypothetical and based on assumed rates of return, which may not reflect actual market conditions. Historical figures cited here are factual records, not forecasts or guarantees of future performance. Individual results will vary. Consult a qualified financial professional before making decisions. CompoundFig does not provide personalized financial recommendations.

Sources & References

  • •S&P Dow Jones Indices — S&P 500 index overview and methodology: spglobal.com/spdji
  • •New York University Stern School of Business — historical returns on stocks, bonds, and bills (annual S&P 500 total returns): pages.stern.nyu.edu
  • •Motley Fool — "The S&P 500 has compounded at 9.98% a year since 1928" (total return, dividends reinvested).
  • •Investopedia — S&P 500 average annual return ≈ 10.09% (1928–Q3 2026).