Market Breadth

A set of indicators that measure how many stocks are participating in a market move versus how many are going the other direction. The advance-decline line, percentage of stocks above their 200-day moving average, and new high-new low ratios are common breadth metrics. When a major index hits new highs but breadth is narrowing -- fewer stocks doing the heavy lifting -- it often signals a weakening rally that may be setting up for a correction.