The biggest near-term concern is probably sentiment. Signals continue to accumulate suggesting both the fast "Tinder trader" crowd and the "long-term commitment" investors are feeling pretty comfortable, perhaps overly complacent right now. The VIX under 12 is not in itself a sell signal; it largely reflects how calm the market has been lately, and the prospect of a sleepwalk toward the holidays.
But when expectations of short-term volatility get this low, stocks can become susceptible to little windstorms started by unassuming butterflies. (Might the ECB see inflation nearer to its target and not promise more QE? Will we get a DJT tweet hostile to some beloved company or sector? Who knows?) The weekly Investors Intelligence bull/bear poll probed further into the happy zone with bulls near 39 percent and bears below 20 percent. The CNNMoney Fear/Greed Index is at 79 on the 100 scale. It was higher briefly in the summer, but once it gets up near 80 there tends to be pretty limited immediate upside.