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3 min readTapeboard Staff

What is a Bear Market? Definition, Formula, and Example

A bear market is a decline of 20% or more in a broad market index from its most recent closing peak, typically lasting months and accompanied by contracting earnings and elevated volatility.

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Bear Market Definition

A bear market is a decline of at least 20% in a broad equity index from its most recent closing high. The 20% threshold is the standard used by S&P Dow Jones Indices and Bloomberg to classify market cycles. Anything between 10% and 19.9% is a market correction. A bear market is confirmed only when the index closes below the −20% line, and it ends retroactively at the closing trough from which the index later rallies 20% — the start of the next bull market.

How a Bear Market Is Identified

The measurement mirrors the bull-market rule:

1. Peak identification. Mark the highest closing price of the index during the preceding bull market.

2. Confirmation threshold. When the index closes 20% below that peak, a bear market is declared, dated from the peak.

Formula: Bear confirmed when Index close ≤ 0.80 × Peak close.

Analysts then assess severity using:

  • Depth. The median post-WWII S&P 500 bear market decline is roughly −30%; recessionary bears average −35% to −40%.
  • Duration. Median peak-to-trough duration is about 12 months; recovery to the prior peak takes roughly 2 years on average.
  • Volatility regime. The VIX sustains readings above 25 during bear markets versus a long-run median near 17.
  • Breadth collapse. The advance-decline line and percent of stocks above the 200-day moving average fall below 20% at bear-market lows.

Worked Example: The 2022 Bear Market

The S&P 500 peaked at a closing high of 4,796.56 on January 3, 2022. Applying the rule:

  • Bear threshold = 4,796.56 × 0.80 = 3,837.25
  • The index first closed below that level on June 13, 2022, at 3,749.63 — officially confirming the bear market 161 days after the peak.

The decline continued to a closing trough of 3,577.03 on October 12, 2022, a total peak-to-trough loss of −25.4%. The Nasdaq-100 fared far worse: QQQ fell roughly −35% peak to trough, and former leaders like META dropped −77% from their 2021 highs before bottoming. The bear ended retroactively at the October low once the S&P 500 rallied 20% off it, confirmed in mid-2023. The full round trip — peak to trough to new all-time high — took just over two years, matching the historical average.

When Traders Use the Bear Market Framework

  • Regime filters. Systematic strategies cut gross exposure, tighten stops, or flip net short when the index trades below its 200-day moving average during confirmed bears.
  • Hedging. Bear markets are when tail-risk hedges, protective puts, and bear put spreads pay off — and when the cost of that insurance, driven by elevated implied volatility, is highest.
  • Bear-market rallies. Counter-trend rallies of 10–20% are a defining feature: the 2022 bear produced three separate rallies exceeding 12% before the final low. Traders treat these as bear traps in reverse — shorting opportunities, not regime changes.
  • Accumulation planning. Long-horizon investors use bear-market drawdown tables to size staged entries, since every historical bear has eventually resolved to new highs.

Limitations and Common Misconceptions

  • The 20% line is arbitrary. A 19.9% drawdown feels identical to a 20.1% one. The label changes nothing about positioning.
  • Confirmation is late. By the time a bear is declared, the index has already fallen 20%; selling at confirmation historically locks in losses near the middle of the decline, not the start.
  • Not all bears are recessions. The 1987 crash (−34%) and 1966 bear occurred without economic recessions. Recession-linked bears are deeper and longer, but the categories don't map one-to-one.
  • "Bear market" says nothing about speed. 2020's bear took 33 days peak to trough; 2000–2002 took 31 months.