1. Ebola headline risk
2. IS continued advances
3. Russia (which facilitated the Germany slowdown)
Projecting earnings through December we can see at current SP500 levels, the market will have a multiple of high 16s. The market is either discounting lower earnings or being inefficient.
The market conditions were the same as they were a month ago: low rates, decent earnings, robust US economy. The difference, fear has allowed the market to correct.