Breadth thrust - GetProfitable

The best-known version is Martin Zweig's, which measures a ten day average of advancers as a share of all issues moving from below 40 percent to above 61.5 percent within a short window. Variants use volume or the mcclellan-oscillator.

The rationale is that a sudden, broad surge in participation reflects a genuine shift in demand rather than a bounce led by a few names, and historical instances have a notably good record of being followed by strong returns.

The sample is small. Breadth thrusts are rare by construction, which means the impressive hit rate rests on a handful of observations spanning decades, and definitions have been adjusted over time in ways that flatter the record. Treat it as suggestive context, not a system.

See it drawn

Original diagrams for the ideas on this page. Illustrative, not real market data.

The stochastic oscillator. The stochastic shows where each close sits inside the recent high-to-low range, on a scale of 0 to 100. Readings above 80 mean closes are hugging the top of that range and below 20 the bottom; the circle marks the fast line turning up through the slow one.