The Associated Press Twitter account was hijacked today by "Anonymous", who sent a fake report:
"Breaking: Two Explosions in the White House and Barack Obama is injured via @AP"
It was accompanied by a black-and-white avatar showing the Guy Fawkes mask over crossed swords. Not a great deal of subtlety there.
The posting caused a two minute decline followed by a three-minute recovery in the S&P 500. Here's the chart:
Bottom line: The best trading strategies in the world count for nought when battered by the wings of a black swan, even if it's a phony swan.