Market Breadth is A technique used in technical analysis that attempts to gauge the direction of the overall market by analyzing the number of companies advancing relative to the number declining. Positive market breadth occurs when more companies are moving higher than are moving lower, and it is used to suggest that the bulls are in control of the momentum. Conversely, a disproportional number of declining securities is used to confirm bearish momentum.
（The graph） Hang Seng Index; (Bottom graph） Line chart showing Moving Average (15 days) of percentage (%) of advancing stocks. The two grey bands are "zone" between which the moving average operates as an oscillating signal.