Essentially, the A/D Line calculates daily or weekly shifts by adding the total number of advancing stocks and subtracting declining ones, creating a cumulative measure. Positive market breadth—where more stocks advance than decline—indicates bullish momentum, while a greater number of declining stocks suggests bearish pressure. Observing these shifts helps investors confirm trends or spot potential reversals when there’s a divergence from index performance.
For instance, if an index like the S&P 500 rises while the A/D Line declines, this suggests waning momentum, signaling that the uptrend may stall or reverse. Conversely, a falling index paired with a rising A/D Line hints at potential recovery.