Bull vs Bear Markets: What Actually Changes

A bear market is a fall of 20% or more from a high. A bull market is the sustained rise that follows one. Those are the definitions almost everyone uses, and they are worth knowing mostly so you can notice how arbitrary they are: nothing happens to a market at 19.6% that does not happen at 20.1%. The number is a convention for headlines, not a mechanism.

What is genuinely useful is the shape of the two, because they are not mirror images of each other. Bulls last longer, drift upward, and are boring. Bears are shorter, faster, and produce the most violent upward days you will ever see. If you only know the definitions you will be surprised by that second part, usually while short.

The arithmetic nobody likes

Start with the one fact in this whole subject that is not open to interpretation. A 50% decline requires a 100% gain to get back to even. Not a 50% gain. A hundred.

This is just division, but it drives more real-world outcomes than any market opinion. It is why risk management is front-loaded, why traders who survive are the ones who cut early, and why a strategy that wins often but occasionally gives back half an account is a losing strategy wearing a good win rate. Drawdowns compound against you at a worse rate than gains compound for you.

It also cuts the other way, which is the part people forget. A 100% gain followed by a 50% decline puts you exactly back where you started. The gain feels like progress and the decline feels like a setback, and arithmetically they cancel.

What each one actually looks like from a chair

Bear markets rally hard. Short-covering produces some of the fiercest single-day moves in the record, and they characteristically burn out with no follow-through. Prices often open higher and fade into the close. Underneath the drama, volume is frequently listless, and the initial furious selling gives way to a long grinding decline that nobody wants to talk about because it is dull.

Bull markets do the opposite and do it quietly. The daily pattern is an early loss or a piece of bad news that gets absorbed by lunchtime and finishes on a firm close. Pullbacks are modest and slow. Volume tends to be high and frequently sets records as prices make new highs.

The practical read is that the same daily behaviour means opposite things in the two regimes. A strong close is confirmation in one and a trap in the other, which is why traders who learned in one environment struggle badly in the next.

Valuations move with the mood, not just the earnings

Price-to-earnings ratios swing far more than the underlying businesses do. At the peak of the dot-com era in 2000 the S&P 500 P/E was near 45. In the bear market of 1981 to 1982 it reached as low as 7. Those are the same kind of companies being valued by the same kind of investors, six times apart.

What changes is what people will pay for a dollar of earnings, and that is a sentiment number. It is also why "the market is expensive" has never been a usable timing signal on its own. Expensive can get considerably more expensive first.

How long they last

The infographic below was made in 2020, and its historical averages are as of then: across the previous 13 bear markets the average duration was 18.5 months with an average decline of 35.2%, and across the previous 13 bull markets the average was 62.5 months with an average gain of 182.64%.

Treat those as illustration rather than as a forecast, for two reasons. Averages across 13 events have very wide error bars, and the sample has moved since: the S&P 500 entered a bear market in June 2022 and bottomed that October, so any count made in 2020 is already out of date. The durable point is not the specific numbers, it is the asymmetry. Bulls run several times longer than bears, and bears take back a smaller percentage than the bulls delivered, which is the only reason long-term buy-and-hold has worked at all.

What this means if you trade intraday

Mostly it means knowing which movie you are in before the open, because the regime changes what a given signal is worth rather than whether the signal exists.

The same breakout has a different base rate in a market drifting up on rising volume than in one producing violent short-covering rallies that die by noon. The same failed test at a level means something different when the tape has absorbed bad news all week. None of that tells you what to do at 09:35, and anyone selling you a rule that resolves it is selling you a curve fit.

What it does tell you is which mistakes are expensive right now. In a bear, holding a winner too long is cheap and holding a loser is ruinous. In a bull, the cost lands the other way round, on cutting good positions early because you have been trained to flinch.

If you want to see how that read gets built in real time rather than described after the fact, our desk runs live every session and you can sit in for three trading days.