Investors behaving badly — Canadian Capitalist. “while the S&P 500 has returned 8.35% over a 20 year period ending in 2008, the average equity investor earned just 1.87%, which was less than the inflation rate of 2.89%. Bond investors fared no better. They earned returns of just 0.77% compared to 7.43% for the index.” Summary of a great report about average investors buying and selling at the worst times.