Trader Brian Jones on Twitter: "It's amazing how much you need to know. Like since tomorrow is 9/11 I had to cover my S&P short. before the bell. I mean if you don't know that. You're in trouble." / Twitter

It's amazing how much you need to know. Like since tomorrow is 9/11 I had to cover my S&P short. before the bell. I mean if you don't know that. You're in trouble.