The Only Three Questions That Still Count: Investing By Knowing What Others Don't, 2nd Edition

What Causes a Bear Market?

There’s simply no single answer to the question: What causes a bear market? It might be monetary conditions, yield curve shifts, surpluses, a sector implosion, excess demand reverting or bad legislation impacting property rights. But it likely won’t be what it was last time. Two bear markets in a row rarely start with the same causes because most investors are always fighting the last war and are prepared for what took them down last time.

Maybe you suspect a bear market will start because the bull market has run on too long. Question One—is there a “right” time a bull market needs to last? No! There is no “right” length for a bull market. As bull markets run longer than average in duration, there is normally a steady stream of folks who say a bull market must end because it’s too old. (Read more on this phenomenon in Markets Never Forget.) That isn’t right. They all end for their own reasons and will end eventually—but age isn’t among them. People started saying the 1990s bull market was too old in 1994, only about six years too soon. “Irrational exuberance” was first uttered in 1996—again, way too early. Bull markets can die at any age.

Use your Questions to test some of these. Find a few of your favorite indicators and see if they’ve reliably led to bear markets before. You will find there is no fundamental indicator on its own, no technical indicator on its own, no single silver bullet, no nothing on its own perfectly predicting when a bear market ...