From a seasonality standpoint, there isn’t a more reliable time of the year to have a pullback than this upcoming week. Since 1961 (and over most every time period) the week following the 3rd Friday in September has produced the most bearish results of any week. In the 9/24/12 blog I showed a chart of SPX performance during this week since 1961. I have updated that chart below.
As you can see the bearish tendency has been pretty consistent over the last 52 years. There was a stretch in the late 80’s where there was a series of mild up years. Since 1990 it has been pretty much all downhill, and last year was no exception.