The Volume Oscillator displays the difference
between two moving averages of a security's volume. The difference
between the moving averages can be expressed in either points or
percentages.
Interpretation
You can use the difference between two moving
averages of volume to determine if the overall volume trend is
increasing or decreasing. When the Volume Oscillator rises above zero,
it signifies that the shorter-term volume moving average has risen above
the longer-term volume moving average, and thus, that the short-term
volume trend is higher (i.e., more volume) than the longer-term volume
trend.
There are many ways to interpret changes in volume
trends. One common belief is that rising prices coupled with increased
volume, and falling prices coupled with decreased volume, is bullish.
Conversely, if volume increases when prices fall, and volume decreases
when prices rise, the market is showing signs of underlying weakness.
The theory behind this is straight forward. Rising
prices coupled with increased volume signifies increased upside
participation (more buyers) that should lead to a continued move.
Conversely, falling prices coupled with increased volume (more sellers)
signifies decreased upside participation.
Example
The following chart shows Xerox and 5/10-week Volume
Oscillator.
I drew linear regression trendlines on both the
prices and the Volume Oscillator.
This chart shows a healthy pattern. When prices were
moving higher, as shown by rising linear regression trendlines, the
Volume Oscillator was also rising. When prices were falling, the Volume
Oscillator was also falling.
Calculation
The Volume Oscillator can display the difference
between the two moving averages as either points or percentages. To see
the difference in points, subtract the longer-term moving average of
volume from the shorter-term moving average of volume:
To display the difference between the moving
averages in percentages, divide the difference between the two moving
averages by the shorter-term moving average: