If you invested $100 in the S&P 500 at the beginning of 2020, you would have about $117.87 at the beginning of 2021, assuming you reinvested all dividends. This is a return on investment of 17.87%, or 17.87% per year.
This investment result beats inflation during this period for an inflation-adjusted return of about 15.17% cumulatively, or 15.17% per year.
The graph below shows the performance of $100 over time if invested in an S&P 500 index fund. The returns assume that all dividends are automatically reinvested.
This chart shows the rate of gains and loss by month, including dividends:
The nominal return on investment of $100 is $17.87, or 17.87%. This means by 2021 you would have $117.87 in your pocket.
However, it's important to take into account the effect of inflation when considering an investment and especially a long-term investment. You can convert S&P returns to their real (inflation-adjusted) value using an inflation calculation based on the U.S. Bureau of Labor Statistics Consumer Price Index (CPI).
In the case of the returns described above, the CPI in 2020 was 258.812 and the CPI in 2021 was 264.877.
The ratio between these CPIs describes how relative buying power of a dollar has changed over 1 year.
Adjusted for inflation, the $117.87 nominal end value of the original $100 investment would have a real value of roughly $15.17 in 2020 dollars. This means the inflation-adjusted return is 15.17% as opposed to the original 17.87%.
For more information on inflation, see our U.S. inflation calculator for 2020.
The table below shows the full dataset pertaining to a $100 investment, including gains and losses over the 12-month period between 2020 and 2021.
Note that data shown is the monthly average closing price. Returns include dividends.
|Year||Month||Return (%)||Amount ($)|
The information on this page is derived from Robert Shiller's book, Irrational Exuberance and the accompanying dataset, as well as the U.S. Bureau of Labor Statistics' monthly CPI logs.
Note that S&P index value for the current quarter is based on a moving average of closing prices, per Robert Shiller's methodology. The inflation data used is based on annual CPI averages.
Average monthly close
Average monthly close
|Change in price||
+-100.00% / yr
|Change incl. dividends||
+17.87% / yr
Final amount, nominal
Final amount, inflation-adjusted