Bubbles and Crashes
Why Smart People Keep Getting Fooled by Bubbles
Every financial bubble in history was obvious in hindsight — and almost invisible to the intelligent, well-informed people living through it.
The Idea
A bubble isn't just a market that has gone up a lot. It's a market where the price of an asset has detached from any reasonable estimate of its underlying value — and where that detachment is being sustained by a shared belief that prices will keep rising. The belief, in other words, becomes the engine. This is what makes bubbles so slippery: they feel rational from the inside. If you buy a tulip bulb, a Florida swamp lot, or a dot-com stock in 1999, and the price doubles in six months, that looks like vindication, not delusion. The market seems to be confirming your judgement. The problem is that a rising price in a bubble isn't evidence of value — it's evidence of momentum. And momentum, by definition, eventually runs out. What usually punctures a bubble isn't a sudden revelation that the asset was always worthless. It's a small shift in sentiment — a whisper of doubt — that triggers selling, which triggers more doubt, which triggers more selling. The cascade is fast and brutal precisely because the original price was held up not by fundamentals but by collective confidence. John Maynard Keynes described markets as a beauty contest where you're not picking who you think is most beautiful, but who you think everyone else will think is most beautiful. In a bubble, everyone is watching everyone else — and when the crowd turns, it turns together.
In the World
The dot-com bubble of the late 1990s is the most instructive modern example, partly because it involved companies that were genuinely changing the world, which made the mania harder to dismiss. Cisco, a company that makes the physical infrastructure of the internet, saw its share price rise over 600% between 1995 and its peak in March 2000. At that peak, Cisco briefly became the most valuable company on earth — priced at roughly 150 times its annual earnings, at a time when a typical healthy company might trade at 15–20 times. The case for Cisco wasn't absurd: the internet really was going to be enormous. But the price had long since stopped reflecting the internet's actual trajectory and started reflecting something else — a story, a feeling, a fear of missing out. Fund managers who knew the valuations were insane kept buying anyway, because their performance was measured quarterly and underperforming the bubble was a career risk. The bubble peaked on March 10, 2000, and over the following two years, roughly 5 trillion in market value evaporated. Cisco itself fell 86% — and didn't return to its peak price for over twenty years. The technology was real. The prices were not.
Why It Matters
Knowing that bubbles exist and knowing you're inside one are two very different things — and the gap between them is where most people lose money. The insight that actually helps isn't "be careful out there" but something more specific: your own excitement is a data point worth examining. When an investment feels obvious, when everyone around you seems to be getting rich, when the story about why this time is different feels genuinely compelling — that's precisely the moment to ask what price would need to be true for this to make sense. Not whether the underlying thing is real or interesting, but whether the price reflects a sober estimate of future returns or a consensus mood. You don't need to call the top. You just need to notice when you're buying a story rather than a business. That distinction — between the narrative and the numerics — is one of the more durable things you can carry into any financial decision, including ones that have nothing to do with stock markets.
A Question to Ponder
Can you think of something you currently believe is a good investment — and honestly separate how much of that belief is based on numbers versus how much is based on a story you find compelling?
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