How to read Volume Change
What the hatched and hollow bars mean, and how the time window works.
Lesson 1 of 24 min read
Draft — this lesson will be expanded soon.
What is being measured
Volume is cumulative for the day. Volume Change is the volume traded during the selected window — for example, the last 15 minutes.
Reading the bars
- Hatched bars show an increase in volume during the window.
- Hollow bars show a decrease (rare for cumulative volume; it can happen if the data source revises figures).
- Turn on Show Volume to see the full-day bar behind the change.
Where the data comes from
The server stores snapshots of per-strike volume at regular intervals during market hours. If the app started tracking after the window began, the change is measured from the first snapshot instead, and the page tells you so.