For some reason, it is quite common to have a reversal on the day’s main trend before 12 o’clock (NYSE time). Yesterday, 26th of September 2017, was one of such days that this happened. The same happens quite often, and you can go back to your charts and check how many times this has happened.
I don’t know the reason behind this behavior. One could argue that it responds to the need of closing the open positions before the lunch break. But is the lunch break such a religious matter? Is there a set of restaurants in NYC that offer special discount or food to the first customers? Or is just a matter of getting the tables with the best views? Whatever it is we better be aware of it. In a day like yesterday knowing this unwritten rule could have given you a good profit.