Studies · Volume
Negative Volume Index (NVI)
negativeVolumeIndex · Fosback's index compounding returns on lower-volume bars
Drawn in its own panelReads volume
Hover the chart to read values · practice data: a seeded random walk with no overnight gaps
What it measures
An index that only moves on days when volume fell. On those days it compounds that day’s price change; on higher-volume days it stays flat. The idea is that informed money trades on quiet days.
How traders use it
- Fosback's rule: NVI above its one-year (about 255-day) moving average signals a bull market backdrop; below it, caution.
- Compared with the Positive Volume Index to see whether quiet-day or busy-day trading is driving the trend.
Parameters
| Name | Value | Default | Allowed | What it does |
|---|---|---|---|---|
| start | 1000 | any usual 100–10000 | The value the index starts at. It only sets the scale. |