The greater fool theory is the informal name for buying an asset at a price above what its own income or use would justify, in the expectation of selling it to someone who will pay more still. The value being paid for is the resale, not the asset. The term is informal, a label for a pattern of speculation rather than a defined model, and no one owns it. A 2010 report on investor behavior prepared by the Library of Congress's Federal Research Division for the Securities and Exchange Commission, for instance, notes that some writers "equate momentum investing, which is a manifestation of magical thinking and herd behavior, with the Greater Fool Theory."
Greater Fool Theory
The greater fool theory is the idea that a buyer can profit from paying more for something than it is worth, as long as someone else, a "greater fool", will later pay even more. It works only while such a buyer exists.
Last reviewed by Steven Fox, CFP®, EA
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Quick Summary
- The bet is on the next buyer, not on the asset: the purchase makes sense only if someone will pay a higher price later.
- It is an informal label for a pattern of speculation rather than a formal model, and it appears in an investor-behavior report the Library of Congress prepared for the SEC.
- Sophie Moinas and Sébastien Pouget's "bubble game", tested in laboratory experiments, shows how an asset everyone knows is worthless can still trade at rising prices when no trader can be sure of being the last buyer.
- Each buyer can be acting rationally on their own terms, yet the chain must end, and whoever holds the asset when buyers run out bears the loss.
- A plain test for any purchase is whether you would still want it if you could never sell it.
Definition
Advanced Explanation
Why it can be rational for one buyer and ruinous for the last. A buyer who pays more than an asset is worth can still come out ahead if a later buyer pays more again. The difficulty is the end of the chain. Economists have studied the logic in the laboratory: Sophie Moinas and Sébastien Pouget's 2013 paper in Econometrica describes a "bubble game" in which participants trade, one after another, an asset that everyone knows is worthless. Because no trader can be sure of being last in the sequence, the game can sustain a bubble even in equilibrium when there is no cap on the maximum price, and they ran experiments with and without such a cap. The point for a household is that "someone will pay more" is a statement about other people's behavior, not about the asset, and it fails all at once when the buyers stop.
How it relates to bubbles. An asset bubble is the market-wide episode in which prices run far above fundamentals. The greater fool theory is the individual buyer's reasoning inside one: I know the price is high, but I expect to sell higher. A bubble can be fed by greater-fool buying, by honest optimism about the future, or by both, which is why the two terms are related but not the same.
What it is not. Buying an asset because its price is rising is not automatically greater-fool reasoning, though the investor-behavior report prepared for the SEC records that some authors treat momentum investing that way. The distinction is whether the buyer has a view of what the asset is worth apart from its resale. An investor who buys shares for the company's earnings is relying on the business; an investor who buys an asset with no income and no use other than resale, at any price, is relying entirely on the next buyer. Assets that pay no income are not greater-fool assets by definition; the label describes the buyer's reasoning, not the object.
How to Remember
Ask who the greater fool is going to be. If the honest answer is "I hope someone after me", the price is resting on hope, not on the asset.
Used in a Sentence
“Ignacio admitted his reason for buying the token was pure greater fool theory: it produced nothing, and his only plan was to sell it to someone who had arrived later.”
How It Works
The pattern runs in three stages. Early buyers pay prices that later buyers are willing to beat, so profits are real and visible. Those visible profits draw in new buyers whose main reason for buying is the expectation of selling higher. When new money stops arriving faster than holders want to sell, the price has nothing beneath it except whatever the asset is worth on its own, and the last buyers absorb the loss.
For example, suppose Ignacio pays $2,000 for a collectible that sells for $500 in a quiet market and produces no income. He expects to sell it for $3,000 within a year. If he finds that buyer, his gain is $3,000 − $2,000 = $1,000, or 50 percent. If interest fades and the market returns to $500, his loss is $2,000 − $500 = $1,500, or 75 percent. Nothing about the collectible changed between the two outcomes; only the supply of later buyers did. The test of whether the purchase was a greater-fool bet is whether he would have paid $2,000 to own it with no prospect of resale.
Pros and Cons
Pros
- The label gives a quick, honest test for a speculative purchase: is the expected profit coming from the asset or only from the next buyer?
- It explains why prices can run far beyond any valuation for a time, and why the fall can be sudden.
- It separates the individual buyer's reasoning from the market-wide phenomenon of an asset bubble.
Cons
- It is informal and loosely defined, so it is easy to throw at any asset someone dislikes.
- Whether an asset is overpriced is usually clear only afterwards, so the theory is better at describing risk than at identifying it in real time.
- Speculation that profits from a later buyer is legal and sometimes successful, which makes the risk easy to underestimate.
People Also Asked
Answers to the most frequently asked questions.
Is the greater fool theory a real economic theory?
It is an informal label rather than a formal model. It describes buying something for more than it is worth in the hope of selling to a later buyer at a higher price. Economists have studied the same logic, for example in Moinas and Pouget's 2013 experiments on bubbles in an asset known to be worthless.
What is an example of the greater fool theory?
Buying an asset that produces no income and has no use beyond resale, at a price far above its recent market value, because prices have been rising and someone else is expected to pay more. If later buyers stop arriving, the price can fall back toward what the asset is worth on its own.
How is the greater fool theory different from an asset bubble?
An asset bubble is the market-wide episode of prices rising far above fundamentals. The greater fool theory is the reasoning of an individual buyer during such an episode: paying a price they believe is too high in the expectation of selling higher. One describes the market, the other a motive.
How can an investor tell if they are relying on a greater fool?
Ask whether the purchase would still make sense if the asset could never be sold, judged on whatever income, use or value it provides on its own. If the only path to a profit runs through a later buyer paying more, the investment rests on that buyer.
Sources
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