@Bright30 Please correct me if I'm wrong but a gap only exists if a security trades above or below the previous days price range without being filled. It is irrelevent where a share opens or closes all that matters is that over a two day period prices are not gapping as shown on the chart. You logic of using opening and closing prices is illogically because shares could go down heavily in one day and then open slightly higher than the close as news is digested and never retest the closing price. The only caveat to the above example is that the opening price is within the range of the previous days price action.