S&P 500: $ 100 in 1965 â † '$ 21,973.23 in 2021 If you invested $ 100 in the S&P 500 in early 1965, you get about $ 21,973.23 in early 2021, assuming you reinvested id all dividends. This is an investment return of 21,873.23%, or 10.11% per annum.