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Advance Decline Line
Advance/Decline Line - A/D
Image 1 A technical analysis tool representing the total of differences between advances and declines of security prices. The advance/decline line is considered the best indicator of market movement as a whole, stock indices such as the DJIA only tell us the strength of 30 stocks where as the A/D line provides much more insight.
Image 2 If the markets are up but there are more declining stocks than advancing ones it's usually a sign that the markets are losing their breadth. If the number of advancing issues are dominating the declining issues and the market is then said to be healthy. If it is falling, then the market is not healthy.


Arms Index (TRIN)


Breadth of Market

Technical Analysis