Are You Investing… or Just Looking for a Greater Fool?

Why the Greater Fool Theory explains more about market bubbles than most investors realise.

Imagine someone offers you a rare collectible for $10,000.

You don’t really think it’s worth that much.

You buy it anyway.

Why?

Because you’re convinced someone else will happily pay $15,000 next month.

Congratulations—you’ve just relied on the Greater Fool Theory.

Most of us like to believe we’re rational investors. We analyse numbers, study charts and follow the latest market news. Yet many investment decisions are quietly driven by something far more powerful than spreadsheets:

Our expectations about what other people will do.

That simple psychological shift has fuelled countless market booms—and painful crashes.

Most people think successful investing is about finding assets that will rise in price.

As a result, they spend much of their time searching for “the next big thing”—the next high-growth stock, cryptocurrency, property hotspot or trending investment.

The assumption is simple:

“If the price keeps going up, buying today must be a good idea.”

But rising prices alone tell us very little about whether an investment is actually becoming more valuable.

Behavioural finance teaches us that markets are not driven solely by facts.

They are driven by people.

And people are influenced by psychological biases, including:

• Fear of Missing Out (FOMO) when everyone else appears to be making money.
• Social proof, assuming something must be a good investment because many people are buying it.
• Overconfidence, believing we’ll know exactly when to sell.
• Recency bias, assuming recent price increases will continue indefinitely.

Eventually, investing stops becoming a question of value.

Instead, it becomes a game of predicting whether someone else will pay even more.

This is exactly what economist John Maynard Keynes described as the Castle-in-the-Air Theory, which later became widely known as the Greater Fool Theory.

The danger is obvious.

The strategy only works until the next buyer disappears.

One observation has become increasingly clear throughout my own investing journey and my conversations with clients.

Very few people lose money because they cannot calculate intrinsic value.

Many lose money because they struggle to separate price from value.

When everyone around us appears excited about an investment, our brains naturally assume the crowd knows something we don’t.

That instinct was useful for survival thousands of years ago.

It isn’t always useful in financial markets.

As The Value Steward, I believe better investing begins with better thinking.

Behavioural finance isn’t about predicting tomorrow’s prices.

It’s about recognising how our own psychology influences today’s decisions.

Whenever you’re evaluating an investment, try viewing it through these three questions.

1. Value

What is this investment actually worth?

Does it produce earnings, cash flow or long-term economic value?

2. Narrative

Why are people buying it today?

Is enthusiasm driven by improving fundamentals—or by excitement, headlines and social media?

3. Psychology

Would I still want to own this investment if I couldn’t sell it tomorrow?

Or am I relying on finding someone willing to pay a higher price?

The wider the gap between value and narrative, the more cautious I become.

Economist John Maynard Keynes understood this psychological dynamic remarkably well.

He illustrated it through his famous “beauty contest” analogy.

Imagine a newspaper competition where participants must choose the six most attractive faces from one hundred photographs.

The prize doesn’t go to the person who chooses the faces they personally find most attractive.

Instead, it goes to the person who best predicts what everyone else will choose.

Markets often behave the same way.

Investors aren’t always asking:

“What is this business worth?”

They’re asking:

“What will everyone else think it’s worth next month?”

Ironically, Keynes used this understanding of market psychology to become one of the most successful investors of his generation. Rather than blindly following the crowd, he recognised that understanding human behaviour could provide an investing edge—but he also appreciated the importance of long-term business value.

Before making your next investment, pause and ask yourself these questions:

• What evidence supports this investment’s intrinsic value?
• If prices stopped rising tomorrow, would I still want to own it?
• Am I buying because I understand the business—or because everyone else seems excited?
• What assumptions am I making about future buyers?
• Am I investing, or am I speculating?

These questions won’t eliminate investment risk.

But they can reduce the risk of becoming the “greater fool.”

Successful investing isn’t just about analysing companies.

It’s about understanding people—including yourself.

Markets will always experience periods when excitement pushes prices beyond fundamentals. The investors who consistently make better decisions aren’t necessarily those with the highest IQs. They’re often the ones who recognise when psychology is replacing rational analysis.

Sometimes the wisest investment decision is the one you choose not to make.

Have you ever bought an investment mainly because you believed someone else would pay more for it later?

Looking back, what did that experience teach you?

I’d love to hear your thoughts in the comments.

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