What Is a Bull Market?
Bull market is the conventional label for a sustained rise, usually a gain of twenty percent or more from a recent low. The threshold is a convention rather than a measurement, and the label can only be applied after the move it describes has already occurred.
A bull market is a description of something that already happened, phrased as though it were a condition you are currently inside. That distinction is the whole of what is worth knowing about the term.
How it works
The conventional threshold is a 20% rise from a recent low. Cross it and the period gets the label, retroactively, back to the low it started from.
The number is arbitrary. It matches the bear-market threshold for symmetry and has no basis in measured market behaviour. Nineteen percent and twenty-one percent are different labels and the same event.
And it is applied backwards. The starting point is the low, which is only identifiable once price has moved far enough away from it — so the label always arrives late by exactly the size of the threshold.
Why it carries no actionable information
Direction runs on this site’s shared series average 2.01 bars with a longest of 11. A sustained rise is built from many of those runs, and the market does not know it is in one.
So “we are in a bull market” says the last stretch went up. It contains no statement about the next bar, and the run lengths above are the reason: persistence exists but it is short and unevenly distributed.
The one measured thing that does point forward is continuation after a breakout: 85% of the 39 twenty-bar breakouts on this series kept going in the breakout direction. That is a specific, testable statement — and it is about breakouts, not about labels.
A worked example
Suppose an index falls 30%, then rises 25% from the low.
Has a bull market started? By the convention, yes — 25% exceeds the threshold. And the index is still about 12% below where it began.
So a portfolio can be in a bull market and underwater simultaneously. The label measures distance from the low; your position measures distance from what you paid. Those are different questions and only one of them is yours.
On this site’s series 95% of bars sat below a prior peak while the stretch finished +3.61% overall. The label and the experience routinely disagree, and the experience is what governs whether people hold on.
The one useful reading
As a description of regime, not a forecast. Knowing that the recent past has been broadly rising is genuine context — it changes how a pullback should be interpreted and how much confidence a long position deserves.
As a caution about sizing. Extended rises are where risk tolerance quietly expands, because recent losses have been small and recoveries fast. The size chosen in that environment is the size carried into the next decline.
And as a reminder that it ends without notice. There is no announcement, and the top is identifiable only from a distance.
The original data
On this site’s shared series: direction runs average 2.01 bars with a longest of 11. Breakouts continued in 85% of 39 twenty-bar events. 95% of bars sat below a prior peak, and the stretch finished +3.61%. A round trip costs 0.0098, about 2% of the median bar range of 0.493.
The 2.01-bar average is what makes the label so weak as a forecast. The market’s own memory is approximately two bars long; a label describing months of history is not connected to that mechanism in any way that helps.
Secular and cyclical
A distinction worth having is between long and short versions. A secular bull market runs for a decade or more and contains several declines inside it; a cyclical one runs for months or a couple of years and sits inside a larger structure that may point the other way.
Both get called bull markets, which is where a great deal of confusion comes from — two people can disagree entirely while both being correct about different timeframes.
Neither is identifiable in advance. The secular label in particular is applied with decades of hindsight, which makes it excellent history and useless for a decision made today.
The practical version is to fix your horizon first. Decide whether the question is about the next year or the next twenty, then read the structure at that scale and accept that the other scale may disagree. Choosing the timeframe after seeing which one supports the position you want is how the label gets used to justify rather than to inform.
When it fails
The characteristic failure is increasing size because the label is favourable. An extended rise makes losses feel small and brief, risk tolerance expands to match the recent past, and position sizes grow into an environment that has been unusually forgiving. The label did not cause this and it supplies the justification for it. When the conditions change — with no announcement and no threshold crossed until long afterwards — the sizing set by the good period is the sizing carried into the bad one.
A second failure is treating the label as a timing signal. It is applied retrospectively and says nothing about duration.
A third is confusing being in a bull market with being profitable, which the 30%-down-25%-up example separates.
A fourth is expecting a symmetric ending. Rises tend to be gradual and declines abrupt, so the exit is rarely as orderly as the entry.
And a fifth is assuming everything rises together. An index can advance on a handful of names while most constituents fall, which breadth measures and the index price hides.
Related
Bear market covers the mirror label and the recovery arithmetic. Market trend covers the structural definition and real run lengths. And breakout covers the one measured continuation figure on this site.
Bull markets are identified in retrospect and discussed as though they were a current state. By the time something has risen enough to earn the name, the rise that earned it is already in the price — which does not mean sell, it means the label contains no information you can act on.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.