Advancing-Declining Issues is a market momentum indicator used to show the difference between advancing issues and declining issues on the New York Stock Exchange. This information is used to determine the strength of the market on a daily basis.

The formula for the Advancing-Declining Issues is simple:

Advancing Issues - Declining Issues

This calculation is is the basis of many market breadth indicators, including the Advance/Decline Line, Advance/Decline Ratio, Absolute Breadth Index, Breadth Thrust, McClellan Oscillator and Summation Index. Indicators that use advancing and declining issues in their calculations are called market breadth indicators. Plotted by itself, this indicator is helpful to determine daily market strength. Strong up days can have readings of more than +1,000. Very weak days can have readings of under -1,000.