The Advance/Decline Ratio (A/D Ratio) illustrates the ratio of advancing issues to declining issues. This is used to display market breadth and while similar to the Advancing-Declining Issues, the A/D Ratio remains constant regardless of the number of issues that are traded on the New York Stock Exchange (which has steadily increased).

This indicator's value is demonstrated by its ability as an overbought/oversold indicator. When the indicator moves towards its upper limits this is inidcative of a overbought situation and implies a correction may occur soon. When the indicator is towards its lower limits this is indicative of an oversold situation and suggests a technical rally is due. Day-to-day fluctuations of the Advance/Decline Ratio are often eliminated by smoothing the ratio with a moving average.