Bear market and stock market crash: how the two relate

Why do a bear market and a stock market crash run on different clocks?

A bear market is measured in months or years, and the common test is a decline of 20% or more over at least two months. A crash is measured in days or hours and is defined by speed and panic. Wikipedia contrasts the two directly: crashes involve panic selling and abrupt price declines, while bear markets build more slowly.

The different clocks explain why the two words are not interchangeable. A reader who hears crash expects a dramatic event this week. A reader who hears bear market expects a long stretch of weak prices. Using the right word sets the right expectation, which matters for any plan that depends on timing.

How can a stock market crash open a bear market?

The 1929 crash is the clearest case. The Dow fell 12.8% on 28 October and 23% across two sessions. By 11 November 1929 it stood 40% below its September high, and it lost 89% of its value before it bottomed in July 1932. The crash was the first and fastest stage of a very long bear market.

March 2020 shows the same opening on a shorter scale. After a 6-day slide into correction territory, the Dow entered a bear market on 11 March 2020, about 20% below its record high. The crash days came first, and the bear label arrived once the cumulative fall passed the line.

Can a stock market crash happen inside a bear market?

Yes. The bear market that began at the Dow peak of 9 October 2007 ran to 6 March 2009 and cut the Dow by 54% to 6,469. Inside that slide came the week of 6 to 10 October 2008, when the Dow fell more than 1,874 points, or 18%, its worst weekly decline on record.

Such crash weeks often mark moments when credit, confidence, and forced selling converge. They add speed to an existing decline. For a reader, the lesson is that a bear market contains smaller events of different tempo, so a rally after a crash week does not always signal the end of the larger phase.

Does a bear market always include a stock market crash?

A bear market does not need a crash. In 2022 the S&P 500 peaked at 4,796 on 3 January and fell 25% by October, with a decline of 21% in the first 6 months, the worst start to a year since 1970. Its largest single-day drop was 4.32%, on 13 September 2022.

That path was a grind: steady losses, frequent rallies, and no single day of collapse. The pattern explains why some investors felt a bear market without seeing a crash. It also shows that depth and duration can do the damage while speed stays moderate, which suits the label bear market better than crash.

How does a bear market fit into the bull and bear cycle?

Markets move through rising and falling phases. A bull market is a period of generally rising prices, usually counted from a 20% rise off a low until a 20% drawdown. Morningstar data cited by Wikipedia for 1926 to 2014 gives bull markets an average of 8.5 years and bear markets an average of 13 months.

A crash can end a bull market abruptly, or a bull market can fade without one. The detailed page on bear market vs bull market follows the cycle step by step and shows what each phase rewards. Knowing the phase tells you which kind of risk dominates, and it helps you size decisions to the stage you are in.

How do you test for a bear market and date the last one?

Two practical questions follow. The first is whether the market is in a bear market now, which depends on the 20% test and the two-month condition. The page on are we in a bear market walks through the test with a simple worksheet that you can repeat after each session.

The second is when the last one happened and whether a crash started it. The page on when was the last bear market lists the recent episodes with dates and shapes. Together the two pages turn a vague impression into a dated record, which is the foundation for any reasoned view of risk.

What should a decision maker do with the link between bear markets and crashes?

Plan for both clocks. A crash plan covers liquidity for the first days, with enough cash to avoid forced selling. A bear plan covers the long phase, with spending needs, review dates, and rebalancing rules. This page is general information, not investment advice. Written rules for each clock keep decisions steady when headlines turn loud.

If your decision depends on how a global fall would reach your exposure, a 30-minute pre-diagnostic with EQOS Asia applies the same structural scoring to your case. You bring the decision, and the session returns a measured view of how much fall your position can absorb.

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About the author

Stéphane Jambu

President, EQOS Forecast Asia

Stéphane Jambu leads EQOS Forecast Asia and works as a consultant in e-commerce, search visibility, and AI. LinkedIn profile