Volume
The number of shares, contracts or units traded during a period.
Also called: traded volume · turnover
Written by Javier Sánchez Ros
In plain language
Volume measures participation. A move on heavy volume involved many participants; the same move on thin volume involved few and is easier to reverse.
It is most useful as confirmation. A breakout on strong volume carries far more weight than an identical break on a quiet afternoon.
Volume has strong time-of-day and seasonal patterns. Comparing a lunchtime hour to the opening hour without adjusting for that is misleading.
Worked through
The same breakout on 3× volume and on half volume
- Average daily volume
- 1.2m shares
- Breakout on 3.6m
- real participation
- Breakout on 600k
- a probe
- Stop fill quality
- follows the same ranking
Volume is the number of shares that changed hands, so it measures how many participants were involved rather than how far price moved. A break carried by three times the usual volume had people behind it; the same break on half the usual volume was a handful of orders moving price through thin air.
The second reading matters just as much and gets less attention. Volume is available liquidity, and available liquidity is what your stop needs on the way out. A position taken in a low-volume session has a stop that will fill into a thin book.
The strongest confirmation is when volume rises on moves in the direction of the trend and falls on the pullbacks against it. That is participation supporting the move rather than drifting through it, and it is visible without any indicator.
Two cautions: volume has predictable daily shape — heavy at the open and close, thin in the middle — so it must be compared against the same period, and a single heavy session can be a fund rebalancing rather than an opinion about the stock.
Why it matters
Volume is a direct read on available liquidity, which determines how well your orders will fill and whether your stop can be executed near its price.
Common mistakes
- Comparing raw volume across sessions with very different baselines.
- Reading high volume as bullish. Every trade has a buyer and a seller.
Keep exploring
These concepts are connected. Understanding one usually makes the next one easier.
How easily an asset can be bought or sold without moving its price.
When price moves decisively beyond an established support or resistance level.
The average price over a session, weighted by the volume traded at each price.
A histogram showing how much volume traded at each price level rather than in each period.
How much and how quickly an asset’s price moves over a given period.