Trading Volume, What is it?

Trading volume is the number of shares exchanged in a stock over a session or period. It is an important gauge of a move's strength: a price rise on heavy volume is stronger and more credible than one on weak volume, because it reflects broad conviction. Volume usually rises around major news, breaks of technical levels, or near earnings. Traders watch for "volume confirmation": a move not backed by volume is suspect. Note the difference between volume (number of shares) and traded value (shares × price). FoudaLens shows volume on each stock's chart and uses it in scoring.