We can divide gap types into two categories: full and partial.
A full gap occurs when the price moves up or down in a single trading session, leaving no overlap between the day’s close and open prices. Partial gaps involve overlap between two trading days, typically caused by an overnight gap that partially fills during regular market hours.
As for how to find gap up stocks, you can find them at any time. However, they are particularly common during earnings season when top line and/or earnings per share numbers beat analysts’ expectations and cause a stock to surge.
An online gap up stocks screener offers an easy way to identify and track gap-up stocks and can enable you to know how to find stocks before they gap up.