Martin Zweig's Breadth Thrust fires when the 10-day advance ratio of NYSE issues (advancing / advancing + declining) swings from below 0.40 to above 0.615 within about ten sessions — a rare, broad-based buying surge historically tied to durable rallies.
A handful of mega-cap stocks can drag an index higher while most shares quietly fall — a narrow, fragile advance. A breadth thrust is the opposite: it captures the moment buying becomes broad and indiscriminate, with the vast majority of stocks rising together. Broad participation is hard to fake, which is why these rare surges have historically marked the early stage of durable up-moves. Example (illustrative): a 10-day advance ratio climbing from 0.35 in a selloff to 0.64 ten days later crosses 0.615 and registers as a thrust.
Genuine Zweig thrusts trigger only a handful of times per decade, so most of the time the signal is simply dormant. And like any single momentum indicator it can produce a false start. Quantustik treats it as one bullish input weighed alongside VIX, credit spreads, and the other signals, not acted on alone.
It uses the 10-day advance ratio: advancing NYSE issues divided by advancing plus declining issues, smoothed over 10 days. A thrust fires when that ratio moves from below 0.40 to above 0.615 within about ten sessions.
It captures broad, indiscriminate buying — most stocks rising together, not just a few mega-caps. Broad participation is hard to fake and has historically marked the early stage of durable up-moves.
Rarely — only a handful of times per decade. Most of the time the signal is dormant, so it is read as a notable event rather than an everyday indicator.
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Educational research only — not investment advice.