"Before March 10, the S&P 500 had stayed above its 50-day moving average for more than 100 days. That has only happened five other times since 1980, says Ryan Detrick, strategist for Schaeffer's Investment Research. After each of those blocks ended, the index rose by an average of 6 percent in the following three months. Four out of those five times, it rose an average of 3.3 percent after just a month."