Demand Index

The Demand Index is a technical oscillator developed by James Sibbett that marries price direction with volume momentum to reveal when a trending move is running out of steam. Unlike volume indicators that measure absolute activity, the Demand Index filters volume through the lens of intrabar price action, giving traders an early warning when a trend is being abandoned even as prices still rise or fall.

How Sibbett’s oscillator actually works

The Demand Index is calculated by comparing the volume on bars where price closes higher than it opened (called “demand” volume) to the volume on bars where price closes lower (called “supply” volume). The formula typically looks at the difference, then smooths it with an exponential moving average. A positive reading means buyers are absorbing more volume; a negative reading means sellers are in control.

What makes this different from a simple uptick-downtick counter is the focus on intrabar direction. A bar with a massive range where price opens near the low and closes near the high still counts as demand, even if the absolute price moved only slightly. Conversely, a small-range bar that closes lower counts as supply. Sibbett argued this granularity captures the moment-to-moment battle between buyers and sellers more accurately than looking at closing price alone.

The divergence signal that matters

A trader’s eye turns to the Demand Index when price and the oscillator stop moving together. If the index reaches a new low while price holds steady or rises, that’s a classic bearish divergence—demand is draining out even as bulls try to push prices higher. Conversely, when the index climbs while price stalls or falls, buyers are quietly accumulating and a reversal upward may be near.

These divergences are not entry triggers on their own; they are yellow flags. A stock making a new high while the Demand Index retreats suggests the rally lacks depth. A double top or breakdown in price on weak index readings carries more weight than the same chart pattern on heavy demand.

Practical use in ranging and trending markets

In a bull-market with strong uptrends, the Demand Index typically stays positive and rises with price. Traders use temporary dips in the oscillator as low-risk entry points—mini-pullbacks where demand has only briefly faltered.

In choppy or sideways markets, the Demand Index oscillates around zero, rarely reaching extreme highs or lows. Readings become less predictive when volume is thin and erratic. During such periods, many traders abandon the tool and wait for the next sustained trend.

The real test comes at turning points. Near major resistance or after a prolonged rally, a failure of the Demand Index to reach prior peaks even as price tags a new high is a signal that the move is tiring. This exhaustion pattern—price higher, momentum lower—often precedes a sharp reversal.

Limitations and why traders still watch it

The Demand Index is lagging by design; it lives in the rear-view mirror of past volume and price bars. A trader cannot act on it in real time, only confirm or question what the chart already shows. It also requires clean, reliable volume data, which intraday traders on lower time frames sometimes lack, especially in thinly traded securities.

The indicator is also heavily dependent on the smoothing period. A short period makes it jittery and prone to whipsaws; a longer period lags price action so much that entry signals arrive too late. Most practitioners use settings between 10 and 20 bars, but no magic number works in all conditions.

Despite these drawbacks, the Demand Index remains respected for one reason: it cuts through the noise of price alone. When price and volume stop dancing together, something is broken in the trend, and the Demand Index makes that break visible before the crowd sees it in the price chart itself.

See also