Accumulation/Distribution Indicator (A/D)

What Is an Accumulation/Distribution Indicator?

The Accumulation/Distribution Indicator, usually shortened to the A/D line, is a technical indicator that combines trading volume with price movement to estimate whether shares are being accumulated (bought steadily) or distributed (sold steadily). It was developed by Marc Chaikin and is typically plotted beneath a stock's price chart. The key idea is that where a security closes within its daily range reveals who is in control. A close near the high suggests buyers dominated, while a close near the low suggests sellers did.

How It Is Calculated

The calculation has three steps. First, the Money Flow Multiplier measures the closing position within the day's range:

Money Flow Multiplier = ((Close - Low) - (High - Close)) / (High - Low)

The multiplier ranges from -1 to +1. A close at the high gives +1, a close at the low gives -1, and a close midway gives zero. If the high and low are equal, the multiplier is set to zero to avoid dividing by zero.

Second, the multiplier is applied to the period's volume:

Money Flow Volume = Money Flow Multiplier × Volume

Third, each period's Money Flow Volume is added to a running total. The resulting cumulative line is the A/D line. Only its direction and shape matter, not its absolute level, because the starting point is arbitrary.

Reading the A/D Line

A rising A/D line suggests buying pressure is outweighing selling pressure, while a falling line suggests the opposite. Analysts often watch for divergence between the indicator and price. For example, if a stock's price makes a new low while the A/D line makes a higher low, this may suggest selling pressure is weakening and accumulation is occurring beneath the surface. The reverse pattern may suggest distribution.

Divergence signals are not guarantees. Prices can keep moving against the indicator, so many investors use the A/D line alongside other tools rather than on its own.

Advantages and Limitations

The indicator uses both price and volume, so it captures information that price alone does not show. It is also simple to calculate and is available on most charting platforms.

Its limitations are real. Because each period's multiplier depends only on that period's open-close-high-low relationship, a small move that closes near the high can register as strongly as a large one. Results also depend on the chosen time frame and the quality of the volume data. Related measures such as Chaikin Money Flow build on the same multiplier, and volume-based tools such as On-Balance Volume take a different approach. Like all technical indicators, the A/D line describes past trading activity and cannot confirm future results.