volume describe the number of shares that have traded for a given security or in the market overall. rises and drops in a security's price can be an indicator of increased or decreased trading activity over a period of time, but the underlying volume or number of trades gives more concrete measurement of investor ? in demand for that stock. a trade generally has two involved parties, the buyer and the seller. the seller is liquidating the shares while the buyer is purchasing them. when measuring trade volume, the only thing calculated is the total number of shares that are traded ?. this calculation can also indicate liquidity especially with high volume stocks which are more easily sold. volume can spike and drop out of the range of a stock's average daily trading volume. for example, cal's comics has an average daily trading volume of 750,000 for the past three months. on tuesday, the volume for cal's comics ? to 1,000,000. this can mean that there is increased investor interest in cal's comics or that institutional investors such as mutual fund managers are trading a large number of it's shares for funds and other managed investments. volume can also help investors anticipate a security's future movement. if one sees a repetitive change in volume that seems ?, they can research what happens at that time of year, whether hits an earning statement release or an important stage of the business cycle.