Accumulation/Distribution

The A/D line calculation uses three steps:

Step 1 — Money Flow Multiplier (MFM): MFM = [(Close - Low) - (High - Close)] / (High - Low)

This value ranges from -1 to +1. If the stock closes at its high, MFM = +1 (all volume is accumulation). If it closes at its low, MFM = -1 (all volume is distribution). If it closes at the midpoint of the range, MFM = 0 (volume is neutral).

Step 2 — Money Flow Volume (MFV): MFV = MFM x Volume

This assigns a direction and magnitude to each day's volume. A day with 10 million shares traded and a close near the high contributes significantly to accumulation. The same volume with a close near the low contributes to distribution.

Step 3 — A/D Line (cumulative): A/D = Previous A/D + Current MFV

The A/D line is a running total of money flow volume. It has no fixed scale — what matters is the direction and slope of the line, not the absolute value.

Key insight: The A/D line's power comes from the money flow multiplier. A stock that trades 5 million shares but closes near its low (MFM near -1) shows institutional distribution — heavy selling into whatever buying exists. The same volume with a close near the high (MFM near +1) shows accumulation. This intraday close position reveals intent that raw volume alone cannot show.

The most valuable use of the A/D line is spotting divergences between the indicator and price. Divergences often precede significant price moves by days or weeks.

Bearish divergence (distribution under the surface): Price is making higher highs, but the A/D line is making lower highs or trending flat. This means that despite rising prices, volume is concentrated near the lows of each day's range. Smart money is selling into strength — distributing shares to retail buyers. This divergence often precedes a meaningful price decline.

Bullish divergence (accumulation under the surface): Price is making lower lows, but the A/D line is making higher lows or trending upward. Despite falling prices, volume is concentrated near the highs of each day's range. Smart money is accumulating — buying the weakness while retail traders panic. This divergence often precedes a strong rally.

How to confirm a divergence is actionable:

1. The divergence should last at least 5-10 bars (not a single-bar fluke)
2. Volume should be above average during the divergence period (institutional-sized)
3. Look for additional confirmation from other indicators (RSI divergence, MACD crossover)
4. The stock should be at a meaningful support or resistance level

Divergences are warnings, not timing signals. A bearish divergence can persist for weeks while the stock continues higher. Use the divergence to tighten stops and reduce position size, then let price action trigger the actual exit.

The A/D line and OBV are both cumulative volume indicators, but they process volume data differently.

OBV approach: Classifies each day's entire volume as either buying (if the close is above the previous close) or selling (if the close is below). There is no nuance — a stock that closes $0.01 higher gets all its volume counted as buying, even if it sold off 5% intraday and barely recovered.

A/D approach: Weights volume by where the close falls within the day's range. A stock that closes near the high of the day gets most of its volume classified as accumulation, regardless of whether the close is above or below the previous day's close. This intrabar sensitivity is the A/D line's key advantage.

When A/D is better than OBV:

• When stocks have frequent inside bars or small gap openings (where the close-to-close comparison is ambiguous)
• When you want to detect intraday distribution patterns (stock rallies intraday but consistently closes weak)
• When analyzing stocks with high institutional ownership (institutions trade throughout the day, affecting where the close lands within the range)

When OBV is better than A/D:

• For gap analysis — OBV correctly captures the gap direction's volume, while A/D only looks at the intraday range
• For stocks that frequently close at extremes (near high or low) where the MFM distinction has less value

Best practice: Use both together. When both OBV and A/D show the same divergence, the signal is stronger. When they disagree, investigate why — it often reveals something interesting about the stock's trading dynamics.

Trend confirmation: When the A/D line trends in the same direction as price, the trend is healthy and supported by volume. An uptrend with a rising A/D line is more sustainable than one with a flat or falling A/D line.

Breakout validation: Before a stock breaks out of a chart pattern, check whether the A/D line has been trending higher during the consolidation. Accumulation before a breakout means institutional buyers have been building positions — the breakout has committed capital behind it. A breakout without prior accumulation is more likely to fail.

Sector-level analysis: Apply the A/D concept to sector ETFs to identify whether money is flowing into or out of a sector. A sector with rising prices but falling A/D is distributing — institutional money may be rotating out even as retail continues buying.

Screening filter: Use the A/D line's 20-day slope as a screening criterion. Stocks with a rising A/D line trending higher over the past 20 days are being accumulated. Combine this with relative volume and momentum filters for a high-quality candidate list.

Earnings play analysis: Before earnings, check the 2-3 week A/D trend. Stocks being accumulated ahead of earnings (rising A/D) often suggest that informed buyers expect a positive report. Heavy distribution before earnings is a warning sign. This is not predictive on its own, but it adds a useful data point to earnings analysis.

Marc Chaikin developed Chaikin Money Flow (CMF) as a bounded version of the A/D concept. Rather than using a cumulative running total (which has no scale), CMF sums the money flow volume over a period (typically 20 or 21 days) and divides by total volume over the same period.

CMF = Sum(MFV, 20 periods) / Sum(Volume, 20 periods)

CMF oscillates between -1 and +1:

• CMF above 0 = net accumulation over the lookback period
• CMF below 0 = net distribution
• CMF above 0.25 = strong accumulation
• CMF below -0.25 = strong distribution

CMF vs A/D line: CMF is easier to read because it has defined bounds and a zero line. The A/D line's cumulative nature makes it harder to compare across stocks or time periods. However, the A/D line captures longer-term institutional accumulation/distribution trends that a 20-day CMF might miss.

Practical use: CMF is useful as a quick screening filter (CMF > 0 = accumulation, CMF < 0 = distribution). The A/D line is better for spotting divergences and long-term trends. Many traders use CMF for screening and the A/D line for deeper analysis on candidates that pass the screen.