Market Breadth

A measure of how many individual stocks are participating in a market move, used to gauge whether a rally or decline is broad-based or driven by just a few large names.

Market breadth indicators look beneath the surface of major index moves. A rising S&P 500 can mask a situation where only a handful of mega-cap stocks are driving gains while hundreds of others are flat or falling. Narrow breadth is a warning sign; historically the best and most durable bull markets are characterized by broad participation across sectors and market-cap sizes.

Common breadth indicators include the Advance/Decline Line (a running tally of stocks rising vs. falling), the percentage of stocks above their 200-day moving average, the New Highs vs. New Lows ratio, and the McClellan Oscillator. When major indexes make new highs while breadth indicators diverge — failing to confirm — technicians call this a "negative divergence" and treat it as a caution signal.

Breadth analysis is particularly useful at turning points. Broad deterioration in breadth often precedes index-level declines, giving attentive investors a heads-up before the headline numbers deteriorate. Conversely, improving breadth during a recovery suggests genuine buying interest rather than a narrow, fragile bounce.

This definition is for informational and educational purposes only. Nothing on Finance Compass constitutes financial, investment, or trading advice. Always conduct your own research and consult a qualified professional before making financial decisions.