US stock futures rebound to flat

The S&P 500 gained 23 points on Friday to close at the highest since late August. It followed at 31 point rally on Thursday after the ECB cut.

Ahead of today's open, S&P futures had been down by as much as 6 points but have rebounded to unchanged.

One reason for caution

Using data 1957, technical analyst John Kosar of Asbury Research found that "the fourth week of October, which is [this] week, is seasonally the weakest of the entire fourth quarter."

The obvious catalyst for selling would be a hawkish Fed.