Positive Volume Index

What is the Positive Volume Index?

The Positive Volume Index (PVI) is the mirror of the Negative Volume Index: a cumulative line that updates only on sessions when volume rises above the prior session's volume, moving by that day's percentage price change and staying flat otherwise. It shares the same lineage, Paul Dysart in the 1930s and Norman Fosback's 1976 refinement, with the premise turned around: expanding volume marks days dominated by the crowd, so PVI tracks what price does when participation is broad and emotional.

PVI is judged like its sibling: slope and position against a long average of itself, commonly a one-year (255-day) EMA, with the line above its average read as a bullish environment. Fosback himself put more weight on NVI, and PVI is mostly used to complete the pair, showing whether crowd-driven days confirm or contradict what the quiet days say.

How traders use it

• As a participation gauge: PVI rising during an advance shows the high-volume days are pushing price up, while PVI falling as price grinds higher suggests the active days are being sold into.
• Against its one-year EMA as a regime filter, read jointly with NVI: both above their averages is the most bullish classic configuration, both below the most bearish, and splits are treated as mixed evidence.
• In divergence work: PVI printing lower highs against higher price highs flags that heavy-participation days are underperforming, a cousin of Volume Divergence on daily data.