Initially analysts thought it was due to low oil prices. Later it was found that a few now unemployed brokers were invested in Chinese hub owned forums. It seems the "Hub" failure may have created a sell off.
For the low oil prices you have me to thank. It is for all the oil stock I own. I figure it is just my luck.
The market has been a yoyo over the past year, this should be expected. i don't like to see the big fast run ups as it only means that it's going to fall soon. For every action there is a reaction. The big funds drive the market so we are at their mercy.