When stocks get toppy and valuations are very high, it doesn't take much to spook the market and for large institutions to hit the sell button. And that's exactly what they did today. http://www.foxbusiness.com/features/2017/08/10/dow-fall-205-points-as-north-korea-tensions-persist.html
Dow Fall 205 Points as North Korea Tensions Persist
Declines in U.S. stocks accelerated Thursday, a pullback that many investors and analysts said had been overdue with indexes at highs and volatility near record lows.