What Is Trading Volume?
Trading volume is the number of shares traded in a given period. Volume confirms price moves — rising prices on high volume signal genuine demand; low volume moves are suspect.
Definition
Trading volume is the total number of shares (or contracts) exchanged during a given period. Volume is displayed as a histogram at the bottom of price charts and is one of the oldest and most important technical indicators.
The core principle: price moves accompanied by high volume are more significant and more likely to continue. A breakout on 3x average volume is far more meaningful than the same price move on 0.5x volume. High volume = conviction; low volume = uncertainty.
Volume analysis includes concepts like volume spikes (potential reversals or breakouts), declining volume in a trend (potential exhaustion), and volume at price levels (volume profile) showing where the most trading has historically occurred.
Real-World Example
A stock has been trending up for months on gradually declining volume — a warning sign of trend exhaustion. Then it sells off sharply on 4x average volume. This high-volume selling day (a 'distribution day') signals institutional selling and may precede a deeper correction.
Why It Matters
Volume is the 'voting machine' of the market — it shows where real money is committed. Price without volume confirmation is the market's equivalent of a rumor; price with volume confirmation is a fact.
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Frequently Asked Questions
What is average daily volume?
Average daily volume (ADV) is the mean number of shares traded per day over a recent period (usually 20-50 days). It's used as a baseline to assess whether current volume is high or low. A stock trading at 3x its ADV is highly active; at 0.3x ADV it's very quiet.
What does it mean when a stock has a volume spike?
A volume spike (a day with 3-5x+ normal volume) often marks a turning point. On a downtrend, a volume spike can signal capitulation — panicked sellers exhausting themselves, potentially marking a bottom. On an uptrend, a spike can signal a climactic blow-off top.
Does low volume mean a stock is bad?
Low average daily volume means the stock is illiquid — wide bid/ask spreads and difficulty entering/exiting large positions. For most retail traders, stocks with less than 500k shares/day average volume are hard to trade. Illiquid stocks can move violently on small orders.
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