Bull vs. Bear Markets Explained: What They Mean and How to Invest in Each

"Bull" and "bear" are two of the most common words in investing. A bull attacks by thrusting its horns upward; a bear swipes its paws downward. On Wall Street, a bull market is a sustained period of rising prices and optimism, while a bear market is a sustained decline accompanied by fear and pessimism.

Understanding these market seasons — and how ordinary investors have historically fared through them — is one of the most valuable lessons in investing. It helps you stay calm when headlines turn scary and avoid overconfidence when everything seems to be going up.

How Bull and Bear Markets Are Defined

The most widely used definitions are based on the S&P 500:

• Bear market: a decline of 20% or more from a recent high.
• Correction: a decline of 10% to 20% from a recent high. See our guide to stock market corrections.
• Bull market: commonly dated from the low point of a bear market, after prices have risen at least 20%.

These thresholds are conventions, not laws of nature, but they give investors and journalists a shared vocabulary.

What Causes Bear Markets?

Bear markets usually have one or more of these triggers:

• Recessions, which shrink corporate earnings.
• Rising interest rates to fight inflation, which lower stock valuations. Our guide to how the Federal Reserve moves the stock market explains this.
• Financial crises, such as the 2008 housing and banking collapse.
• Bursting bubbles, like the dot-com crash of 2000–2002.
• Sudden shocks, such as the COVID-19 pandemic in early 2020.

What Fuels Bull Markets?

Bull markets typically ride on growing corporate profits, a healthy economy, stable or falling interest rates and rising investor confidence. Earnings growth is the engine; sentiment is the accelerator.

How Long Do They Last?

History shows a striking asymmetry. Since World War II, US bear markets have generally been shorter — often lasting months to around a year or so — while bull markets have frequently lasted several years. Bull markets have also produced far larger cumulative gains than bear markets produced losses. This is why the long-term trend of the US market has been upward, despite frequent setbacks.

Of course, there are painful exceptions. The decline from 2000 to 2002 lasted more than two years, and it took the Nasdaq around 15 years to regain its 2000 peak. Diversification matters.

How to Invest in a Bull Market

• Stay disciplined. Rising markets tempt investors to take more risk than they intended.
• Rebalance. As stocks rise, they become a larger share of your portfolio. Our rebalancing guide explains how to bring it back in line.
• Avoid chasing hot themes or buying with borrowed money.

How to Invest in a Bear Market

• Don't panic sell. Selling after a big drop locks in losses and risks missing the recovery — some of the market's best days have historically come close to its worst days.
• Keep investing regularly. Dollar-cost averaging buys more shares at lower prices.
• Check your emergency fund so you never have to sell stocks to pay bills.
• Review your risk tolerance — honestly. If a bear market keeps you awake, your allocation may be too aggressive. See our guide to managing stock market risk.

Key Takeaways

• A bear market is a 20%+ decline; a correction is 10%–20%.
• Bear markets have historically been shorter and less extreme than the bull markets that follow.
• Staying invested and continuing to contribute has rewarded long-term investors.