Often most stocks and indexes will reverse or pivot from thier initial move around the pivotal time frame. The first of these major pivotal time frames is the 10:00 am or first half hour of trading. While this phenomenon occurs very often it is not 100% and does not occur every trading day. Therefore, it is always important to put it together with another resistance level or possibly a pattern to increase the odds of a short tern trend change. The next minor pivotal intraday time frames are 10:30 and 11:00 am ET. The time frames after lunch are: minor -1:00 pm, and the major afternoon time frames are 2:30 pm, 3:00 pm, and 3:30 pm. Experiment with the time frames and you see how often these are good turning points throughout the day.