🎯 In 30 seconds: Volume counts how many shares changed hands. On its own it says little. Compared with the stock’s own normal, it shows when a move had broad participation and when it did not. Heavy volume on a breakout or a sharp reversal is a sign of commitment. A climax is an extreme burst at the end of a long move. A dry-up is a quiet pullback that suggests the other side is not pressing. All three are clues to weigh, never signals that act on their own.
Compare a stock with itself
Two million shares is a sleepy day for one company and a frantic day for another. Raw volume only becomes useful once you compare it with that stock’s typical level.
The simplest yardstick is relative volume:
Relative volume = today’s volume / average daily volume over the last 50 days
Hypothetical example: a stock usually trades 2 million shares a day. Today it traded 5 million. Relative volume is 5 / 2 = 2.5. Anything above about 2 is unusual enough to ask why.
During the session, be careful. Trading is usually heaviest just after the open and just before the close, with a lull around midday. If 1.2 million shares have traded by 11 a.m., do not compare that with a full-day average. Compare it with how much normally trades by 11 a.m. If that is 0.6 million, today is running at about twice its usual pace.
Reading price and volume together
Volume is a second witness. It does not tell you where price is going. It tells you how many people showed up for the move you are already looking at.
| Price | Volume versus normal | A reasonable reading |
|---|---|---|
| Breaks out of a range | Well above | Many participants agree. The move has backing. |
| Breaks out of a range | Below | Few people care yet. Treat the break as unproven. |
| Pulls back in an uptrend | Below | Profit taking, not a rush for the exit. |
| Pulls back in an uptrend | Well above | Holders are leaving in size. The trend may be changing. |
| Grinds higher for weeks | Falling steadily | Fewer buyers each day. The advance may be tiring. |
The table gives tendencies. You will find plenty of breakouts on light volume that kept going, and heavy-volume breakouts that failed the next week.
Climaxes: the burst at the end
A climax is a period of extreme volume and an unusually wide price range that arrives after a long, one-way move. It often marks the moment when the last group of holders gives up (after a fall) or the last group of buyers rushes in (after a rise).
Selling climax. After a steep decline, one bar plunges, prints volume several times normal, and closes well off its low. The long lower tail shows buyers stepped in hard before the close.
Buying climax. After a long rally, often with a gap up on news, volume explodes and the bar closes near its low or in the lower half of its range. The eager buyers arrived, and sellers met them.
You can write a climax as a rule so it is testable. Here is one hypothetical version:
- Price has fallen in at least 7 of the last 10 sessions.
- Today’s volume is at least 3 times the 50-day average.
- Today’s range is at least twice the average range of the last 20 days.
- Today’s close sits in the upper half of the bar.
A rule like that will flag some real turning points and some bars that were only a pause before more selling. Test it before trusting it. The testing chapter shows how.
Dry-ups: when nobody presses
A dry-up is a stretch of unusually light volume, often during a pullback or a tight sideways base. The idea is simple. If price drifts lower and very few shares change hands, the sellers are not in a hurry.
In the figure, the retest after the climax comes on the lightest volume of the chart. Price holds above the climax low and turns up as volume returns. That sequence of a heavy low, a quiet retest and then expanding volume on the way up is one of the more readable volume stories.
The honest limit: quiet trading can also mean nobody is interested. A stock can drift lower on light volume for months. A dry-up only becomes useful when price also stops falling.
Days that distort volume
- Index changes. When an index adds or drops a stock, funds that track it trade at the close of one day, producing a huge spike with no change in opinion.
- Monthly options expiration. Hedges get unwound, and volume can jump for mechanical reasons.
- Holiday sessions. Shortened days and the last weeks of December tend to be quiet.
- Earnings and news. Spikes are expected here. Judge them against the stock’s past earnings days, not against a normal Tuesday.
- Splits. Share counts change, so check that the volume history is adjusted the same way as the prices.
The volume indicators chapter turns these ideas into running totals such as on-balance volume and money flow, and the breakouts chapter uses volume to judge whether a break is real.
- A stock averages 800,000 shares a day and trades 2.4 million today. What is its relative volume? Answer: 2.4 million / 800,000 = 3.
- Why is comparing 11 a.m. volume with a full-day average misleading? Answer: Only part of the day has traded, and volume is uneven through the session. Compare with the usual amount traded by that time.
- What marks a selling climax? Answer: After a long decline, a wide bar on several times normal volume that closes well above its low.
- When does a volume dry-up carry meaning? Answer: When light volume comes with price holding or stabilizing, such as a quiet pullback that stays above a prior low.
Sources
- Robert D. Edwards and John Magee, Technical Analysis of Stock Trends (first published 1948)
- John J. Murphy, Technical Analysis of the Financial Markets (1999)
- Perry J. Kaufman, Trading Systems and Methods, further reading
- Moneydesks Technical Analysis tool (Volume indicator and Chart events markers)