Positive Volume Index

Volume

What it measures

PVI is the direct mirror of NVI: it tracks cumulative price changes only on days when volume was higher than the prior day, ignoring quiet days entirely. Where NVI is meant to capture "smart money" behavior on quiet days, PVI is meant to capture the broader "crowd's" behavior on the active, high-volume days typically driven by news, momentum, and public participation.

How readings are interpreted

A rising PVI means price has been advancing specifically on the high-volume days — consistent with broad-based, crowd-driven buying interest. Like NVI, PVI is conventionally read relative to its own long-term moving average rather than as a standalone level.

Conventional levels

PVI above its own long-term (e.g. 255-day) moving average: historically associated with the crowd being net bullish during active trading
PVI below its long-term moving average: less clearly bullish per the same convention
Because PVI only updates on high-volume days, its behavior can be choppier and more news-reactive than NVI's

Where it works, and where it does not

Like NVI, this app computes PVI only for long-term daily analysis, not shorter swing/hourly timeframes, for the same reason — the pattern is only meaningful over a long enough history. Best suited to long-term investors, particularly as a complement to NVI rather than in isolation.

Commonly read alongside

NVI: The natural pair — compare the two to see whether quiet-day ("smart money") and active-day ("crowd") trends agree
Volume spikes/news: PVI reacts specifically to the high-volume days, so it's naturally responsive around news and earnings
Long-term moving averages: Read against its own long-run average, same convention as NVI

Known limitations

On its own, less differentiated from simply watching price trend during high-volume periods
Shares NVI's slow-changing, long-horizon-only character — not useful for short-term decisions
The theoretical basis (crowd behavior on high-volume days) is a generalization, not a guarantee for any specific security

In practice

Use exclusively for long-term, position-level analysis, same as NVI
Most valuable when compared directly against NVI — agreement between the two (both trending the same direction) is a stronger combined signal than either alone
Read relative to its own long-term moving average rather than as an absolute number
Treat as a supporting long-term data point rather than a primary trading signal

Plot it yourself. Add this indicator to a chart, change every parameter and watch the line move, then backtest how the rule would have behaved on historical data — free on the S&P 500 ETF, no card.

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This is reference material, not advice. It describes what each indicator measures and how its readings are conventionally interpreted. Nothing here is a recommendation to buy or sell anything, and no indicator predicts future prices. GU Analyser is an analytical tool — no money is ever traded here.