Probably manual sell off, then automated computer run systems see the dip and sell off before major loss. There was something earlier this year where a news ag

Probably manual sell off, then automated computer run systems see the dip and sell off before major loss. There was something earlier this year where a news agency's twitter account was hacked, and the hacker reported that there was an attack on the white house, and the stock markets went crazy for a bit. http://www.usatoday.com/story/money/markets/2013/04/23/stocks-gyrate-wildly-after-fake-terror-tweet/2107089/ http://www.usatoday.com/story/money/markets/2013/04/23/stock... Edit: Also, the stock was downgraded.