It doesn't update until shortly before 9 Eastern, and auto matically refreshes itself throughout the regular session.
You can also manually refresh it with the refresh icon.
The ticker symbols continously change throughout the day. The placements from No. 1 to 100 also change. New ones are added later in the afternoon if they have risen substantially.
The bar chart program for this list also doesn't include issues priced below 2 dollars. If a stock priced below 2 dollars earlier in the day rises above 2 dollars it often appears on the list.