Accumulation/Distribution Line: Formula and How to Read It

What the accumulation/distribution line measures

The accumulation/distribution line (A/D line) is a running total of volume, weighted by where each session closed within its own high-low range. Marc Chaikin developed it and first called it the Cumulative Money Flow Line. A close near the high adds most of the session’s volume to the total, a close near the low subtracts most of it, and a close at the midpoint adds nothing. The premise is that the close location hints at which side controlled the session, while volume shows how much trading stood behind it.

The line is measured in shares, but its level means little on its own. The level depends on the session where the running total began, so two charts that start on different dates draw the same shape at different heights. What carries information is the direction and slope of the line compared with price over the same sessions.

Money flow multiplier calculation

Each session first gets a money flow multiplier, a number from -1 to +1 that locates the close within the range. It subtracts the distance from the close to the high from the distance from the low to the close, then divides by the whole range. The multiplier times volume is the money flow volume, and the A/D line adds those amounts session by session.

Money flow multiplier = ((Close - Low) - (High - Close)) / (High - Low)
Money flow volume = Money flow multiplier × Volume
A/D line = Previous A/D line + Money flow volume

The numerator simplifies to 2 × Close - High - Low, so the multiplier is positive exactly when the close is above the midpoint of the range. A close at the high gives +1 and a close at the low gives -1. The size of the move does not matter: a session that gains $3 and one that gains 3 cents both score +1 if they close at their highs.

Edge case: when a session’s high equals its low, as in a session where every trade printed at one price, the range is 0 and the multiplier would divide by zero. The usual convention, used in this guide, sets the multiplier to 0 for that session, so its volume neither adds to nor subtracts from the line.

Accumulation/distribution line calculation, worked through

The table follows a hypothetical stock for ten sessions. Each row computes the multiplier, multiplies it by volume and adds the result to the running total, which starts at 0 before session 1. Session 6 applies the zero-range convention, and session 7 is a gap session discussed below.

Check session 3 by hand: the close of $51.05 is $0.85 above the low and $0.15 below the high, so the multiplier is (0.85 - 0.15) / 1.00 = 0.700, and 0.700 × 1,500,000 = 1,050,000 shares added to the line.

How to read the A/D line on a stock chart

Plot the A/D line in a pane below price and compare the two directions over the same sessions. When both rise, closes have tended to finish in the upper part of their ranges on meaningful volume, which is consistent with the advance. When price rises while the line flattens or falls, the gains are coming with weaker closes, or the heaviest volume is arriving on weak closes.

• Compare slopes, not levels: a steeper line means larger money flow volume per session.
• Find the sessions that moved the line most. One heavy-volume session can account for most of a month’s change.
• Keep the same date range for price and the line; changing the start date shifts the line’s level, not its shape.
• Check the volume pane for unusual sessions before drawing conclusions, as described in Understand stock volume.

Accumulation/distribution line divergence

A divergence occurs when price and the A/D line disagree about direction over the same swing. In a bearish divergence, price makes a higher high while the line makes a lower high; in a bullish divergence, price makes a lower low while the line makes a higher low. Chart readers take it as a sign that the closes and volume behind the move are not confirming it.

The illustration in this guide shows a hypothetical bearish divergence: the second advance reaches a higher price, but its sessions close lower in their ranges on heavier volume, so the line computed from those bars peaks lower. A divergence describes past sessions, not the next one. It can last for weeks while price keeps trending, and a single heavy-volume session can erase it, so treat it as a prompt to examine which sessions created the disagreement.

The A/D line during stock price gaps

The multiplier only looks inside the current session, so the A/D line ignores the move from the previous close. A stock that gaps up at the open and drifts lower all day closes near its low, receives a negative multiplier and pushes the line down on a day the stock still finished higher. The reverse happens after a gap down that recovers into the close.

Session 7 in the example shows the effect. The close of $53.70 was $2.30 above the previous close, a gain of 4.47%, yet it sat near the bottom of the session’s $1.60 range. The multiplier was -0.875 and the line fell by 2,800,000 shares, the largest single change of the ten sessions.

When a chart shows a large gap, inspect the gap session on its own before reading a divergence. The guide to stock price gaps covers how gaps form and how to measure them.

Accumulation/distribution line vs on-balance volume

On-balance volume (OBV) is also a running total of volume, but it adds or subtracts the full session volume according to the close-to-close change: added when the close is above the previous close, subtracted when it is below. The A/D line adds a fraction of the volume according to the close location within the range. Applied to the same sessions, the two lines can tell different stories.

Over the ten sessions the close rose from $49.80 to $54.50. OBV ended at 7,300,000 shares, while the A/D line ended at -149,000 shares, mostly because of the gap session. OBV asks whether each session closed higher or lower than the one before; the A/D line asks whether it closed strong or weak within its own range. Neither identifies who traded or why.

Limitations of the accumulation/distribution line

The A/D line compresses each session into one number, and several things are lost along the way. Keep these limits in mind before relying on a reading.

• It ignores the previous close, so gap sessions can move the line against the session’s actual change.
• It ignores the size of the move: a quiet session and a volatile one that both close at their highs score the same multiplier.
• One heavy-volume session can outweigh weeks of ordinary sessions, as session 7 does in the example.
• Its level depends on the start date and its scale on the stock’s volume, so values cannot be compared across stocks.
• Zero-range sessions need a convention, and sources that report different volume totals produce slightly different lines.
• The words accumulation and distribution describe the arithmetic. The line does not identify institutional buying or selling, and it does not forecast the next session.

Data cadence and where to study the inputs

The A/D line works on any bar that has a high, low, close and volume. Daily bars are the most common, and each value then updates once per session after the close. Weekly bars smooth out single-session spikes, and intraday bars track money flow within a day. The line has no lookback period, so it needs only one bar to start; its level simply depends on where the data begins.

TradeClever’s Stock Charts do not plot the A/D line. They show daily candles with a volume pane, which is enough to inspect both ingredients directly: where each session closed within its range and how heavy its volume was.

close > (high + low) / 2 and volumeRatio > 1.5