The number of stocks that are participating in either
the market’s upward or downward movement. If the stock market rises during a
trading session and a large number of stocks also rise, then the market has
good breadth. Inversely, if the market rises, but only a relatively small
number of stocks rise, the upward price movement is said to lack breadth. The
same is true of a declining market. Breadth often is measured by the advance-decline ratio, which compares the
numbers of stocks rising against the number of those that are falling.