what is the 10 a m rule 
some traders follow something called the 10 a m rule the stock market opens for trading at 9 30 a m and the time between 9 30 a m and 10 a m often has significant trading volume traders that follow the 10 a m rule think a stock s price trajectory is relatively set for the day by the end of that half hour for example if a stock closed at 40 the previous day opened at 42 the next and reached 43 by 10 a m this would indicate that the stock is likely to remain above 42 by market close 