Below we highlight the simple rolling ten year return on the S&P 500 since 1955 (note that this is simple return, not total return). The shaded areas on the chart are periods of negative return. The great bull market lasting from 1982 to 2000 brought this calculation has high as 400% before turning negative in October of 2008. With this market up 59% from the bottom, many investors may feel as though they missed these gains and need to wait for another entry point. Depending on your time horizon, that is not necessarily the case.
If we look at the last period when ten year returns were negative, we find that the ten year return going forward is an average of 163%. In other words, on a days when the ten year return on the S&P was negative (this is roughly 640 trading days) the average return going forward ten years was 163% and the minimum return was 78%. Anyone with a time horizon of at least ten years should stay in stocks.