Breadth Thrust
A breadth thrust is a family of signals that identify a fast expansion in the number or volume of advancing securities, usually after participation was weak or washed out. The shared idea is speed plus breadth; the exact universe, input, smoothing rule, thresholds and time window depend on the named implementation.
"Breadth" is a simple idea: instead of asking whether the market index went up, ask how many individual stocks went up. An index can rise because a handful of giant companies rose while most stocks fell — breadth tells you whether the crowd actually came along.
A breadth thrust is the moment that crowd behavior flips violently: the market goes from most stocks falling to nearly everything rising, within days. Think of a stadium wave — not one section cheering while the rest sit, but the whole stadium on its feet almost at once.
Analysts care because that kind of stampede has historically happened near the start of big recoveries, not in the middle of ordinary weeks. But "breadth thrust" is a family name, not one rule — different analysts define the stampede with different measurements, which is why this page exists.
- Category
- Market breadth
- Entity type
- Signal family
- Also called
- breadth momentum thrust, participation thrust
- Last reviewed
- 2026-08-11
Current observation
This dated measurement is an instance of the concept, not the concept itself. It updates when the verified source dataset changes; the as-of date below is the freshness contract.
The named rule cannot complete until its EMA first falls below 0.400. The last completed event on our disclosed universe was 2019-01-08.
- 10-day EMA
- 0.499
- State
- Neutral
- Completed events
- 6
- Last event
- 2019-01-08
Common implementations are separate signals
Issue count · 10-day EMA · washout-to-surge path inside 10 sessions.
Exact definition →Volume share · one session · no EMA or prior sub-0.400 setup required.
Live volume signal →Multi-day advance/decline or volume sums · thresholds and windows vary by author.
Compare breadth gauges →Observed overlap, not shared data: 5 of 6 completed Zweig windows in our record also contained a 90% up-volume day. ZBT uses advancing issue counts; the 90% signal uses volume. The overlap is computed from both published datasets and neither event is a required input to the other.
Why it matters
A price index can rise because a handful of large constituents advance. A breadth thrust asks whether buying has spread quickly across many securities or a very large share of volume.
The speed requirement separates a sudden regime change from a slow repair. Many implementations were designed to flag the transition from liquidation or pessimism to unusually broad demand.
The label alone is incomplete. A Zweig Breadth Thrust, a 90% up-volume day and other breakaway-momentum rules use different inputs and horizons, so their event lists and evidence cannot be pooled without restating the rule.
Calculation and identification
Every implementation must state its universe, participation input, smoothing method, low and high thresholds, and maximum elapsed sessions.
This is the Zweig rule used by our live gauge. It is one member of the breadth-thrust family; the generic definition of every thrust lives on the Breadth Thrust page.
Worked example
Why the rule must be named
Imagine 91% of exchange volume flows into advancing stocks today, while the 10-day EMA of advancing issues rises only from 0.38 to 0.49.
- 1The session qualifies as a 90% up-volume day because the volume threshold was crossed.
- 2The Zweig gauge is armed because its EMA was below 0.40, but it has not reached 0.615.
- 3Follow-through over the remaining window could complete a Zweig thrust; today's volume event cannot complete it by itself.
“Breadth thrust” should be followed by the named rule or a complete formula. Similar intuition does not make two event definitions interchangeable.
Where it can mislead
- 01
There is no single universal breadth-thrust formula. Publishing a signal without its universe, input, thresholds and window makes the observation non-reproducible.
- 02
Issue-count and volume-based measures answer different questions. A market can have broad participation by count without 90% of volume moving the same way, or vice versa.
- 03
Rare-event forward returns come from small samples and overlapping market regimes. Report the full event count and ungraded recent events rather than only a hit rate.
- 04
The absence of a thrust is not a bearish signal. Markets can recover gradually or continue rising without first producing the washout required to arm a particular rule.
Relationships
Concept-to-concept edges are typed and reciprocal. Tools, manuals, signals and datasets are separate resource nodes that measure, explain or operationalize the concept.
The Zweig rule is one named, path-dependent implementation inside the broader breadth-thrust family.
Drawdown measures the price decline from peak within which breadth washouts — the arming condition for thrust rules — typically develop.
Unusual volume applies the same participation-intensity idea to a single security against its own baseline, where a breadth thrust aggregates participation across the whole market at once.
Shows the daily advance/decline participation inputs before a named thrust rule is applied.
Places thrusts inside a broader framework of participation, divergence and trend confirmation.
Implements one named issue-count rule with a daily EMA, armed state and event catalog.
A related single-session volume measure; it uses up-volume, while the Zweig EMA uses advancing issues.
Frequently asked questions
Is a breadth thrust in progress right now?
Our Zweig implementation is not armed as of 2026-08-21, with its 10-day advance-ratio EMA at 0.499. It must first fall below 0.400 before a new completion window can begin. This answers only the named Zweig rule, not every breadth-thrust variant.
How often did a 90% up-volume day overlap the completed Zweig windows?
5 of 6 completed Zweig windows in our published record contained at least one 90% up-volume day. The overlap is computed across two datasets: ZBT uses advancing issue counts, while the 90% signal uses volume, so one is not an input or prerequisite for the other.
Is there one official breadth-thrust definition?
No. Breadth thrust is a signal family. Named implementations differ by exchange or stock universe, issue count versus volume, smoothing, thresholds and window; a reproducible claim must state all five.
Is a 90% up day the same as a breadth thrust?
It is a related volume-based thrust event, but not the same as a multi-session issue-count rule such as Zweig. One extreme session can occur without the sustained EMA move required by Zweig.
Does no breadth thrust mean a rally is weak?
No. Most days and many durable advances do not produce rare named thrusts. The absence of a signal says its setup and speed conditions were not met, not that future returns must be poor.
Sources, provenance and machine access
- What Is a Breadth Thrust and What Are the Risks? →CMT Association
Professional reference for the breadth-thrust concept and its technical-analysis lineage.
- Winning on Wall StreetMartin Zweig / Warner Booksprimary
Original published source for the named Zweig Breadth Thrust rule.
Universe filters, timestamps and reproducibility standards used by our live observations.
Stable ID: https://www.thetrading.tools/concepts/breadth-thrust#term. Dated observations have their own IDs and point back to this term; they never overwrite its definition.