PVI

Summary

Positive Volume Index: a running cumulative index that changes only on days when
volume rises versus the prior day, compounding that day's percentage price change.
The premise is that active, high-volume days reflect the actions of the
less-informed "crowd", so PVI is read as a proxy for that cohort's positioning.

Formula

PVI[startIdx] = 1000

For each subsequent bar i:

PVI[i] = PVI[i-1] + ( inVolume[i] > inVolume[i-1]
                      ? ((inClose[i] - inClose[i-1]) / inClose[i-1]) * PVI[i-1]
                      : 0 )

The index carries forward unchanged on bars whose volume did not rise (and on the
degenerate case of a zero previous close, which would otherwise divide by zero).

Inputs

• inClose — Close price of each bar
• inVolume — Volume of each bar

Outputs

• outReal — Cumulative positive volume index (seeded at 1000)

Properties

Numerical Stability: Path-Dependent

Display Flags
☐ Overlap Input
✅ Independent Y-Axis i
☐ Candlestick

Implementation

TA-Lib Definition: pvi.c · pvi.yaml

Native	File
C	ta_PVI.c
Rust	pvi.rs
Java	Core_PVI.java

TA-Lib is also available for Python, R and more using a wrapper.

Aliases

Positive Volume Index

References

• Norman G. Fosback, Stock Market Logic, The Institute for Econometric Research (ISBN 0917604482)