Breadth Thrust: The Rare Signal That Marks Bull Market Starts
Macro Glossary, Indicators and Reads
By Ken Chigbo, macro trader and founder of KenMacro, 18+ years in markets.
Updated 2026-05-20
The desk’s answer
A breadth thrust is a rare, sharp expansion in market participation that signals genuine capitulation buying. The Zweig Breadth Thrust, defined by Marty Zweig, requires the 10-day ratio of NYSE advancing issues to total issues to rise from below 0.40 to above 0.615 within 10 trading days. Historically the signal has fired roughly 15 times since 1945 and has been followed by an average S and P 500 gain of around 24 percent over the next 12 months with no false signals. Whaley and Coppock variants tighten or loosen the criteria, but the underlying logic is the same: when participation expands violently, the move tends to continue.
Defined term, Breadth thrust
A breadth thrust is a sharp expansion in market participation measured by indicators such as the Zweig Breadth Thrust (advancing issues divided by total issues on the NYSE rising from below 0.40 to above 0.615 within 10 trading days) or the Whaley thrust (an 11-day cumulative breadth measure). Historical thrusts have a strong track record of preceding sustained bull market advances.
How the Zweig thrust is calculated
The Zweig Breadth Thrust uses the 10-day exponential moving average of NYSE advancing issues divided by the sum of NYSE advancing plus declining issues. The signal fires when this 10-day EMA rises from below 0.40 (extreme washout, less than 40 percent of issues participating on the upside over 10 days) to above 0.615 (broad-based buying, more than 61.5 percent participation) within 10 trading days. The compressed timeframe is the point: a slow drift from 0.40 to 0.615 over 6 months is not a thrust, it is a normal recovery. The signal is the violent expansion within a narrow window.
Why breadth thrusts work
Bear market bottoms are characterised by selling exhaustion (most issues already declining heavily) followed by a sudden return of broad-based buying that catches the consensus underweight or short. The 10-day expansion from below 0.40 to above 0.615 captures exactly this rotation: participants who were selling now switch to buying broadly, not just into a narrow set of names. The breadth expansion is therefore evidence that the move is structural rather than a narrow-leadership relief rally that fades. Historical thrusts since 1945 have included 1962, 1975, 1982, 1984, 2009, 2019 and 2023.
How traders use a thrust signal
Three modes. Position traders treat a confirmed thrust as a regime signal: increase equity exposure, lengthen duration on long positions, accept lower cash levels. Tactical traders watch for the thrust to fire and use the first pullback after the signal as the entry, since the immediate post-thrust days often involve digestion. Macro traders read a thrust as confirmation that the risk-off regime has ended and rotate cross-asset positions (sell yen and gold safe havens, buy risk-currency carry, lengthen credit). The signal is rare and slow-moving; it is a tool for sizing the regime, not for daily trades.
Frequently asked
What is a Zweig Breadth Thrust?
A breadth signal defined by Marty Zweig, where the 10-day EMA of NYSE advancing issues divided by advancing plus declining issues rises from below 0.40 to above 0.615 within 10 trading days. It signals broad-based capitulation buying and has a strong track record of preceding sustained bull advances.
How often does a breadth thrust signal fire?
Rarely. Roughly 15 confirmed Zweig thrusts have fired since 1945, averaging less than one every five years. The rarity is part of the value: the signal is not noisy, and historically it has been followed by an average S and P 500 gain of around 24 percent over 12 months.
Do breadth thrusts work outside US equities?
The underlying logic (sudden broad-based participation rotation marking a regime end) is general, but the formal Zweig definition is built on NYSE data. Analogues exist for global equity indices using their respective breadth measures, and the concept has been adapted to cross-asset risk gauges (currency breadth, commodity breadth) with mixed empirical success.
What this means at the desk
Breadth thrusts are a regime read, not a daily trade. When one fires, lengthen the timeframe of every position.
Read next from the desk
Educational glossary entry only, not financial advice and not a trade signal. The desk teaches a reading framework, never entries, targets or recommendations. Trading forex, indices and leveraged products carries significant risk and may not be suitable for all traders. Some broker links on this site are commercial partnerships and KenMacro may receive compensation, which does not change the editorial view. Only trade with capital you can afford to lose.
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