How it works
Price Volume Trend is On-Balance Volume with the crudeness taken out. It keeps the cumulative structure — a running total that only ever grows or shrinks — but instead of adding a bar's whole volume on any up close, it adds a fraction proportional to the percentage change in price. A bar that closes a tenth of a percent higher contributes a hundredth of what a ten-percent bar of the same volume would.
The economic intuition is that a move's significance depends on how far it travelled, not merely that it travelled. Two sessions with identical volume, one drifting up a cent and the other gapping up five percent, are not the same event, and OBV cannot tell them apart. PVT can, which makes it a fairer measure of how much conviction has actually accumulated behind a trend.
The cost of that fairness is sensitivity. Because the percentage change is a multiplier, one violent session dominates the whole series and permanently shifts the line, and a gap contributes at full weight even though no volume traded across the gap itself. In an instrument prone to earnings gaps or overnight news, the PVT line is effectively a record of a handful of events with a lot of small noise around them.
Traders use it exactly as they use OBV: for shape, trendlines and divergence, never for its level, which is an artefact of where the data begins. The most useful move is to run PVT and OBV together. When OBV rises but PVT does not, the up bars have been numerous but small — a drift higher on many quiet sessions. When PVT rises but OBV does not, a few large up moves are doing all the work, which is a very different market.
Read against the wider family, PVT sits between the two extremes: OBV ignores magnitude entirely and the Accumulation/Distribution line ignores the previous close entirely. PVT is the version that pays attention to bar-to-bar price change and its size, and ignores where inside the bar the close landed.
Calculation
The arithmetic in words, in the order it happens.
PVT is cumulative like OBV, but each bar contributes a fraction of its volume rather than all of it. The bar's contribution is its volume multiplied by the proportional change in the close: (close - previous close) / previous close. Add that to the running total each bar. Where OBV asks only whether the close was up, PVT asks by how much, so a small move adds a small amount and a large one adds a large amount. As with every cumulative line, the starting value is arbitrary and only the shape is meaningful.
Source
An AlgoBeamScript implementation of the formula above, written by us from the arithmetic so the code and the calculation agree line for line.
Runs unchanged on the platform and in the AlgoBeamTS runtime. The language reference is in the documentation.
Inputs
Defaults are the values most charting packages ship with. They are conventions, not optimal settings — the right length depends on your instrument and your holding period.
| Input | Default | What it changes |
|---|---|---|
| Lookback | None — the line is cumulative | There is no window to tune; every bar in the loaded history contributes permanently. Changing how much data the chart loads therefore changes the level of the line but not its recent shape. |
| Smoothing | None | An optional moving average over the PVT line, commonly 20 periods. It gives a slow crossover trigger and makes trendline work cleaner, at the price of further delay on a series that is already slow. |
How to read it
What practitioners take from the plot. Read these as descriptions of market state, not as entry signals.
- PVT rising faster than price during an advance
- Volume is concentrated in the larger up moves. The strongest confirmation this family offers, because both magnitude and participation are pointing the same way.
- PVT flat or falling while price makes new highs
- The advance is being made on small moves or on light volume. A quality warning that carries more weight than the equivalent OBV divergence, since PVT accounts for the size of each move.
- PVT rising while OBV does not
- A handful of large up bars are carrying the line while most sessions close lower. Event-driven strength rather than steady accumulation, and it usually needs the event to keep repeating.
- PVT breaking a trendline drawn on its own swings
- The cumulative flow structure has changed. Read as an early warning about the trend, with the price level that defines the trade supplying the actual invalidation.
Limitations
Where this indicator misleads. None of these are fixed by a better parameter.
- Gaps are counted at full weight even though no trading occurred across them, so an earnings gap on heavy volume permanently rewrites the line and every trendline drawn on it afterwards.
- The percentage multiplier makes the series dominated by a few extreme sessions. In practice most of the movement in a multi-year PVT line comes from a handful of bars.
- It is cumulative, so the level is arbitrary, values cannot be compared between instruments, and there is no natural zero or threshold to work from.
- It needs a meaningful close-to-close change, which makes it unreliable on twenty-four-hour markets where the daily boundary is a convention, and unusable where volume is a tick count rather than a traded quantity.
Educational reference. This page explains how an indicator is built and how it is commonly read. It is not investment advice, not a recommendation and not a signal service. No indicator is profitable on its own — each is a way of describing a market, and any rule built on one has to be tested with realistic costs before it is traded.