I had an eagle eye on 3 stocks at 11:50. One had been in a consistent step-down and continued to do so for the next 15 minutes (no reaction) The second one made a 25 cent downward move that was was no larger than 9 other moves it made during the day. The third made a 50 cent move no larger than 7 other moves it made during the day. If I look hard enough I can see "something maybe" happening at 11:50 in two of the stocks and and "something maybe" going on with all three at around 3:15, but they all happened several minutes apart and the price rebounded in each of them at different times (minutes apart). Was it a reaction to the plane crash? Maybe. Was the magnitude of the price movement significant? No. How would it be traded? I don't see how.