These alerts are similar to the previous set of alerts.  While those compare each stock's current price to its price at today's open, these compare the current price to the previous day's close.  Otherwise, these alerts use the same algorithms and historical background data as the previous alerts.

The most obvious advantage to using the previous close is that these alerts work in the premarket.  The previous alerts only report after the opening print.

More importantly, the two types of alerts handle the gap differently.  If you believe that the gap was based on news after the market, and the market has already stabilized, use the previous set of alerts.  Those start fresh after the open, and only look for new changes.  If you think that the gap is significant and will continue to effect the stock prices through the day, use these alerts.  This philosophy is appealing to traders who believe that the beginning of the day is too wild to be predictable or the open is manipulated by the specialists.

More options related to these alerts are listed below.