From The Big Picture:
...It is worth noting that these average returns following quarters of 15%+ performance are nothing out of the ordinary. The average monthly return over all periods in the DJIA since 1900 is 0.58%, the average quarterly return is 1.66%, and the average yearly return is 6.90%. If anything, the average returns following huge quarterly gains actually outpace the average returns during all periods.
Perhaps another way to look at it is these record setting rallies, especially following a a big selloffs, are themselves a form of mean reversion.
Here’s the tabel of past 15% quarters: