One stock records more shares traded than another. That does not necessarily mean more money changed hands in it. Share volume and traded value use different units, so the ranking can change when you switch measures.
The NYSE’s volume-summary description distinguishes total trades, share volume and dollar volume. The same care with units is useful on other market-data screens, even when the labels and coverage differ.
A two-trade example
Suppose 100 shares trade at 10 currency units and another 50 trade at 12. Share volume is 150. The combined traded value is 1,600: 100 multiplied by 10, plus 50 multiplied by 12. There are two transactions in this deliberately simple example.
Multiplying all 150 shares by the final price of 12 gives 1,800, which is not the value of those two trades. Actual transactions occurred at different prices. A closing price is not automatically an average execution price for the session.
Before comparing two screens
Read the period, currency and market coverage. Is the figure for the current session, the previous day or a longer average? Does it include only one venue or consolidated activity? Are extended trading hours included?
Also check whether a display abbreviates quantities in thousands or millions. A number without its scale can look impressive while being impossible to compare accurately with another screen.
High activity alone does not tell you the direction of the next price move or make a trade suitable. Volume can be discussed alongside price and other evidence, but it is not a stand-alone promise of liquidity at the price you want.
When taking notes, write the label and unit beside the number. “150 shares in two trades, worth 1,600 currency units in this example” says considerably more than “volume was 150,” and avoids confusing activity with company value.