Bull Markets and Bear Markets - History and Patterns
A bull market is a sustained rise in stock prices, conventionally defined as an advance of 20% or more from a prior low. A bear market is a sustained decline, defined as a drop of 20% or more from a prior high. These thresholds are arbitrary, chosen for their roundness rather than any economic logic, but they provide a useful framework for categorizing market cycles that have repeated throughout the history of U.S. equities.
Since 1928, the S&P 500 has experienced roughly 27 bull markets and 26 bear markets. The asymmetry in that count reveals the core fact about long-term equity investing: bull markets have produced cumulative gains that vastly exceed the cumulative losses of bear markets. Stocks go up more often, for longer, and by larger magnitudes than they go down.
The Historical Record of Bull Markets
Bull markets have varied enormously in duration and magnitude.
The longest bull market in S&P 500 history ran from March 2009 to February 2020, lasting nearly 11 years and producing a total return of roughly 400%. This bull began at the depths of the financial crisis, when the S&P 500 traded below 700, and ended only because of the COVID-19 pandemic, an exogenous shock that no market analysis could have predicted.
The 1990s bull market (October 1990 to March 2000) ran for nearly a decade and returned roughly 417%, fueled by the technology revolution, globalization, Federal Reserve accommodation, and eventually the dot-com speculative mania.
The post-COVID rally (March 2020 to January 2022) was the shortest major bull market in modern history, lasting less than two years but delivering a roughly 114% gain from the pandemic bottom.
The post-pandemic/AI-driven rally (October 2022 to present) began after the 2022 rate-hiking bear market ended and has been driven by artificial intelligence enthusiasm, strong corporate earnings (particularly from mega-cap technology), and expectations of eventual rate cuts.
Average bull market duration since 1928: approximately 2.7 years. Average bull market gain: approximately 112%. Median bull market gain: approximately 86%. The averages are pulled upward by the extraordinary bull markets of the 1990s and 2010s.
The Historical Record of Bear Markets
Bear markets are shorter, sharper, and more emotionally intense than bull markets.
The 2007-2009 bear market was the most severe since the Great Depression. The S&P 500 fell 56.8% from its October 2007 peak to its March 2009 low, erasing trillions of dollars in household wealth and triggering a global financial crisis.
The dot-com bear market (March 2000 to October 2002) saw the S&P 500 decline 49.1%. The Nasdaq Composite fell 78% from peak to trough. Technology stocks that had traded at astronomical valuations returned to earth. Cisco Systems declined 86%. Intel fell 82%. Qualcomm dropped 85%.
The COVID bear market (February to March 2020) was the fastest in history. The S&P 500 fell 33.9% in just 23 trading days. The speed of the decline was unprecedented, but so was the speed of the recovery: the index reached new all-time highs within five months.
The 2022 bear market saw the S&P 500 decline 25.4% from January to October 2022, driven by the Federal Reserve's aggressive rate-hiking campaign to combat inflation.
Average bear market duration since 1928: approximately 9.6 months. Average bear market decline: approximately 36%. Median bear market decline: approximately 33%.
The numbers confirm what historical observation suggests: bear markets are much shorter than bull markets. The average bear lasts less than a year, while the average bull lasts nearly three years. The average bear market loss is roughly one-third of the average bull market gain. This asymmetry is why long-term investors who stay invested through bear markets have been rewarded historically.
What Drives Bull Markets
Bull markets are sustained by a combination of factors that reinforce each other.
Earnings growth. The most durable bull markets are built on genuine corporate earnings growth. The 2009-2020 bull market saw S&P 500 earnings per share roughly triple, from approximately $60 to $160. Earnings growth driven by revenue expansion, margin improvement, share buybacks, and productivity gains provides a fundamental foundation for rising stock prices.
Accommodative monetary policy. Low interest rates reduce the discount rate applied to future earnings, directly increasing equity valuations. Low rates also encourage borrowing, spending, and risk-taking, all of which support corporate revenue and investor willingness to pay higher multiples. The post-2009 bull market coincided with near-zero interest rates and three rounds of quantitative easing.
Multiple expansion. As investor confidence grows during a bull market, the price-to-earnings ratio expands. Investors are willing to pay more for each dollar of earnings because they expect earnings to continue growing and risks to remain manageable. The S&P 500 P/E ratio expanded from roughly 11x at the 2009 low to over 22x by 2020.
Technological innovation. Several of the largest bull markets have coincided with transformative technological shifts: the railroad expansion in the late 1800s, the post-war industrial boom of the 1950s-1960s, the personal computer and internet revolution of the 1990s, and the mobile computing and AI revolution of the 2010s-2020s. New technologies create new industries, improve productivity, and generate earnings growth that sustains market advances.
Sentiment and momentum. Rising prices attract more buyers, which pushes prices higher, which attracts more buyers. This positive feedback loop does not create value, but it amplifies and extends bull markets. Media coverage of rising markets encourages participation, and the fear of missing out (FOMO) pulls in investors who might otherwise wait on the sidelines.
What Drives Bear Markets
Bear markets are triggered by different catalysts but share common characteristics.
Recessions. Most bear markets coincide with economic recessions. The 2001, 2007-2009, and 2020 bear markets all involved recessions. Recessions reduce corporate revenue, compress margins, and trigger earnings declines that undermine the fundamental support for stock prices.
Monetary tightening. When the Federal Reserve raises interest rates to combat inflation, the higher discount rate reduces equity valuations even before earnings start declining. The 2022 bear market was primarily a "valuation compression" bear, driven by higher rates rather than an earnings collapse.
Financial crises. The 2007-2009 bear market was amplified by a banking crisis that threatened the stability of the entire financial system. Financial crises create a feedback loop: falling asset prices weaken bank balance sheets, which forces credit contraction, which further weakens the economy and asset prices.
External shocks. Wars, pandemics, and geopolitical events can trigger bear markets. The COVID-19 pandemic caused the fastest bear market in history. The 1973 oil embargo contributed to the 1973-1974 bear market.
Valuation excess. Bear markets are often preceded by periods of extreme overvaluation. The dot-com bubble pushed the S&P 500's Shiller P/E ratio above 44, roughly three times its historical average. When valuations are stretched, the margin of error is zero, and any negative catalyst can trigger a violent repricing.
Patterns Worth Noting
Several patterns have held across multiple cycles:
Bear markets end when pessimism peaks, not when fundamentals improve. The March 2009 bottom occurred months before the economy stopped contracting. The March 2020 bottom occurred when COVID cases were still accelerating. Stocks are forward-looking, and they bottom when the market collectively decides that the worst is priced in, not when the worst is over.
The first year of a bull market produces the largest gains. The S&P 500 gained 68% in the first year after the March 2009 low and 75% in the first year after the March 2020 low. Investors who wait for "confirmation" that the bear market is over typically miss a substantial portion of the recovery.
Bear markets become less frequent in the postwar era. The period from 1929 to 1945 included multiple devastating bear markets. Since 1945, bear markets have occurred roughly every 5 to 7 years and have generally been shallower (the 2007-2009 financial crisis being the notable exception).
Secular trends override cyclical movements. Secular bull markets (lasting 10 to 20 years) contain multiple cyclical bear markets within them. The secular bull market from 1982 to 2000 included bear markets in 1987 (the crash) and 1990 (the Gulf War recession). Investors who sold during those cyclical bears and failed to re-enter missed the continuation of the secular advance.
The Psychology of Market Cycles
Bull markets breed complacency. As prices rise year after year, investors increase their equity allocations, reduce their cash holdings, and take on more risk. Near the peak, the prevailing sentiment is that "this time is different," that some structural change has permanently eliminated the risk of a downturn.
Bear markets breed panic. As losses accumulate, investors sell to stop the pain, reduce equity allocations, and demand safety. Near the bottom, the prevailing sentiment is that conditions will never improve, that some structural change has permanently impaired the market.
Both sentiments are wrong at their extremes, and both create opportunities for investors who can resist them. The challenge is that resisting the prevailing sentiment feels uncomfortable and even irrational in the moment. Buying stocks in March 2009 or March 2020 required acting against overwhelming fear. Reducing risk in late 1999 or late 2021 meant accepting the social cost of underperforming a euphoric market.
The historical record offers a reassuring context: every bear market in U.S. history has been followed by a new bull market, and every new bull market has eventually carried prices above the prior peak. The investor who understands this pattern and can tolerate the drawdowns that occur along the way has a structural advantage over the one who cannot.
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