Volume measures a specific thing price alone can't show — how many actual shares changed hands, which determines whether a price move reflects broad conviction or just thin trading.
What Volume Actually Confirms
A price move on high volume (well above a stock's typical average daily volume) reflects broad participation — many market participants agreeing on a direction. The same price move on low volume is statistically weaker and more prone to reversing, since it may reflect just a few trades moving a thinly-traded stock rather than genuine broad demand or supply. This is precisely why breakouts above resistance are judged by accompanying volume, not price alone.
Compare a day's volume against the stock's own 20 or 50-day average volume, not an absolute number — what counts as "high volume" for a small-cap with thin daily trading is entirely different from a heavily-traded large cap, so the comparison must be relative to the specific stock's own baseline.
Someone Evaluating a Breakout's Legitimacy: Check volume against the stock's own average — a breakout on below-average volume warrants skepticism.
Someone Comparing Volume Across Different Stocks: Compare each stock's volume to its own historical average, never to another stock's absolute number.
Use Volume the Way
- Compare volume to the stock's own historical average, not an absolute figure.
- Treat low-volume breakouts with skepticism.
- Use volume alongside price action, never as a standalone signal.
See technical analysis explained for how volume fits into the fuller toolkit.
