Bubbles: When Intellectual Gravity Fails Against Human Mania and Global Crises
In the world of investment, the word “Bubble” is almost always spat out a day too late. Whether it was the Dot-com crash, the Real Estate collapse, or the Crypto winter, these phenomena are nothing new; they are the recurring cycles of greed and structural economic distortions that have replayed themselves for centuries.
The most honest definition of a bubble is “a state where asset prices soar far beyond their Intrinsic Value.” These assets expand continuously like shimmering bubbles—captivating and beautiful on the outside, but hollow within—ready to Burst the moment there is no more “momentum” or “new buyers” to keep pumping in the air.
Let us begin with the data that proves what truly constitutes a bubble. We will start by calculating value; though these formulas may seem headache-inducing, feel free to skip ahead to the next section.
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The Yardstick of “Hollowness”
To prove the presence of “air” in an asset, economists use statistical health checks. However, a word of caution: these tools are not fixed constants.
Market-wide Valuation: Calculating the Index P/E Ratio
We calculate the P/E of an index to view the market’s overall health. There are two primary methods:
1. Market-Cap Weighted Basis: Sum the total Market Cap of all stocks in the index and divide by the total Net Profit.
Stock A: Market Cap 1,000M Baht, Profit 50M Baht (P/E = 20)
Stock B: Market Cap 9,000M Baht, Profit 150M Baht (P/E = 60)
Index P/E Calculation: (1,000 + 9,000) / (50 + 150) = 10,000 / 200 = 50x
As you can see, the Index P/E is “weighted” toward Stock B due to its larger size, reflecting the risk where the majority of the money actually resides.
2. Price-to-Earnings Index Basis:
Index P/E = Current Index Price /Index EPS
The Interest Rate Context: A “normal” P/E (15–25x) is always relative to Interest Rates. When rates are low, a higher P/E is tolerable because the cost of capital is cheap. But when rates rise, the appropriate P/E should decrease.
Extreme Signals: During the 1999 Dot-com bubble, the NASDAQ P/E skyrocketed to 100–200x. This often happened because Earnings (EPS) were near zero or negative, making the denominator so small that the P/E “exploded mathematically.” This is the clearest signal of a structural bubble.
PEG Ratio: The Line Between “Growth” and “Fantasy” in Tech
PEG = (P/E) / (Expected Earnings Growth)
- Caution: PEG is a “forward-looking” tool. It fails instantly if analysts’ estimates are wrong or if a company’s growth is merely a “One-off.” Many bubbles are born from PEG ratios that look great on paper but rely on low-quality earnings, heavy adjustments, or massive Leverage to manufacture the numbers.
The Golden Rule: “P/E and PEG are warning sirens, not final judgments.”
3. The Buffett Indicator: Is the Market “Bigger Than Its Boots”?
One of the tools used by legendary investor Warren Buffett to gauge the big picture is comparing the size of the stock market to the actual economy.
Formula: (TotalMarketCap÷NationalGDP) x 100
Normal Range (75% – 90%): Stock prices are reasonable and align with the actual economic output of the country.
Bubble Territory (120% – 150%+): If this figure hits these levels, it means the “paper wealth” of the stock market has far outpaced the country’s actual productivity. It is like “a bubble that has grown larger than the sink it sits in,” a dangerous sign that the compressed air inside is ready to pop.
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Lessons from a Genius: When “Newton” Fell into the Trap of the Masses
No case study reflects the terror of a bubble better than the South Sea Bubble of 1720 involving Sir Isaac Newton, the genius who discovered the laws of gravity.
What was the South Sea Company? It held a monopoly on trade in South America—a region rumored to hold vast gold reserves—and offered to “underwrite the British national debt” in exchange for interest. This led people to believe the company was “government-guaranteed.”
Why did Newton decide to buy?
The public dreamed of undiscovered gold and resources. Newton began as a rational investor; he bought shares and made a profit early on. But as “mania” swept London—infecting aristocrats, parliamentarians, and the middle class who borrowed money to speculate—even Newton could not resist the gravitational pull.
Statistics show the South Sea share price soared from £128 in January to £1,000 in August within just seven months. Newton jumped back in at the very peak, only for the bubble to burst, crashing to £124 by December of that same year. He lost over £20,000 (equivalent to millions of dollars today), leading him to utter the classic line that echoes through history: “I can calculate the motion of heavenly bodies, but not the madness of people.”
Behavioral Science: Why Does History Repeat Itself?
Deep studies from institutions like Oxford suggest that bubbles aren’t caused by mathematical errors, but by Behavioral Economics. Greed and Herd Behavior overpower analytical thought. The severity of the South Sea Bubble forced the British government to pass the “Bubble Act,” which regulated the incorporation of public companies for a century. It serves as a reminder: whenever the value of a dream is pumped up beyond the capacity of reality, a catastrophe waits at the finish line.
Deep Dive into Hidden Mechanisms: Leverage and the Diffusion of Responsibility
This is the sharpest part of the discussion because bubbles don’t start with “expensive things”; they start with a system that allows people to buy expensive things without actually paying for them.
Invisible Leverage: The Multiplier of Cashless Wealth
Tulip Mania (1637): Buying tulips shifted from trading actual bulbs to Windhandel (Trading in the Wind)—essentially Futures contracts. Investors put down a small Margin to control the rights to bulbs of immense value. If the price moved up just 10%, the investor could double their money. This “leverage” lured millions to pump prices, believing the system would run forever, forgetting that when delivery was due, if no one could pay full price for a real flower, the system would hit zero instantly.
The Dot-com Crisis (2000): High-IQ Wall Street analysts agreed that “new business models” didn’t need profits. The NASDAQ crashed 78% in less than two years. Even the most tech-savvy investors “hit the peak” because they weren’t fighting price; they were fighting FOMO (Fear Of Missing Out).
US Subprime Crisis (2008) and the Laundering of Junk: The era of 100% LTV (Loan-to-Value) arrived—banks lent to homebuyers without a single cent of a down payment. They created complex debt instruments like CDOs (Collateralized Debt Obligations), bundling “Subprime” loans from people with no capacity to pay into an index. Mathematicians used statistical models to slice this junk debt into tiers and slapped on AAA ratings, selling it to the world. When the penniless buyers began to default, the truth that “bundled junk is still junk” exploded into a global economic crisis.
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Moral Hazard: When the Players Aren’t Responsible
Systems produce unlimited risk when the decision-makers are not the ones who suffer the consequences.
- Tulips: “Wind traders” didn’t want bulbs to plant, and sellers often didn’t even have bulbs in hand (Short Selling). Everyone signed paper contracts hoping to sell to a “Greater Fool,” indifferent to whether a real product could ever be delivered.
- Subprime: Banks lent to those with no income because they knew they could immediately sell that debt to other institutions as securities. Since the banks weren’t liable if the borrower defaulted, they lent recklessly while credit rating agencies gave AAA ratings to this garbage just to collect their fees.
When the “Contract” Becomes the Product, Not the “Asset”
This is the most dangerous tipping point: when Derivatives become more expensive and more heavily traded than the underlying asset. The system collapses the moment people ask: “Where is the actual thing?”
- Tulip Era: The real product was a flower; the world spun on “paper tickets.”
- Subprime Era: The real product was a house; the world spun on “CDOs / CDSs.”When reality finally catches up—proving the real assets cannot support those contracts—the bubble bursts violently.
Statistics = Moral Anesthesia
In the Subprime crisis, world-class actuaries used models assuming “average risk is safe,” believing it was impossible for the entire country to default at once. They brushed aside Tail Risk (low-probability, high-impact events). In reality, bubbles always pop because of the very events the models said “would never happen.”
Real Estate Bubbles: Measuring “Income” vs. “Home Price”
In analyzing real estate, economists don’t just look at how much prices have risen, but at the Price-to-Income Ratio.
- The Analysis: If house prices grow 20% a year while wages grow only 3%, the gap is “Debt.” When people can no longer afford payments and there is no “Greater Fool” to buy them out, the bubble bursts because the reality of “no money to pay” eventually catches up to the house price.
- Normal Range: A healthy home price should be roughly 3–5 times annual household income.
- Bubble Peak: During the Subprime crisis or in some modern mega-cities, this ratio has spiked to 10–15 times.
Catalysts: Inflation, Geopolitics, and Forced Circumstance
Modern bubbles have sharper dimensions because they may arise from global pressures.
- Inflation and QE: When rates are low and the system is flooded with cash, people are forced into risky assets just to beat inflation. Prices rise not just from greed, but from a “fear of poverty.”
- Geopolitics: When war creates shortages in energy or minerals, prices are pumped by a “Scarcity Premium” far beyond reality.
- Case Study: China’s Real Estate: This is an example of “Forced Investment.” With strict capital controls and limited alternatives, Chinese citizens poured money into property, leading to “Ghost Cities” with 65–80 million empty units. This reflects a bubble born from smart people trying to protect themselves in a distorted rulebook. Financial innovation isn’t a crime; it becomes a weapon of mass destruction only when used to “inflate price” instead of “manage risk.”
- The “Too Big to Fail” Policy: The belief that the government would never let a sector accounting for nearly 30% of GDP collapse led investors to underestimate risk (Moral Hazard). In 2021, it was estimated that China had enough empty housing to house the entire population of France.
The Greater Fool Theory and Warning Signs
The thread that ties every crisis together is “The Greater Fool Theory” by Burton Malkiel. It states that prices can keep rising as long as we believe we can find a “Greater Fool” to take the baton at a higher price. This mechanism works like a Pyramid Scheme that requires a constant influx of newcomers to keep the momentum going.
The Dot-com Bubble: “Fantasy” vs. “Real Profit”
In 1999, the NASDAQ P/E hit 200x. Many companies with “zero profit” (negative earnings) had massive Market Caps simply because they had “.com” in their name.
- Analysis: If you see a stock priced at $1,000 but it only makes $1 a year in profit (P/E = 1,000), you are buying “Hope,” not a “Business.” When hope fails to materialize, the bubble vanishes.
Checklist: Recurring Bubble Warning Signs
- Returns seem “Guaranteed” despite unusually high Leverage.
- Everyone explains risk using “Mathematical Models” rather than “Common Sense.”
- The Actual Asset begins to be viewed as “Irrelevant” compared to the price on the screen.
Conclusion: When the Bubble Bursts… Who Truly Pays the Price?
A bubble is never born of “greed” alone; it is born of a “system that makes greed look safe.” And when the day comes that the contracts in hand are called to be paid in real cash, the world realizes instantly that “bundled junk is still junk.”
But the saddest part is that the damage rarely stops at the stock ticker. When prices plummet, the Domino Effect hits the real economy:
- Vanishing Corporate Value: When Market Cap evaporates, companies lose the ability to raise capital or borrow to stay afloat.
- Lightning-Fast Austerity: To survive a cash crunch, management’s first move is to “cut costs,” leading to halted projects and Mass Layoffs.
- Structural Collapse: When giants fall, the SMEs and suppliers that depend on them are gutted, leading to business closures and widespread unemployment.
The shockwave of a bursting bubble hits the “Grassroots” and the “Hand-to-Mouth” workers—some of whom didn’t even know the name of the stocks being traded. Operations staff, street vendors, and day laborers become the ones who pay for the “manipulated numbers” they never benefited from. Mindful investing and quality analysis are not just about personal profit; they are a responsibility toward the most vulnerable members of our society.
5 Must-Read Books
1. Extraordinary Popular Delusions and the Madness of Crowds
Why You Should Read It: Consider this the “Bible” of market psychology that every global investor must own. First published in 1841, it remains startlingly relevant today. It provides the most detailed accounts of Tulip Mania and the South Sea Bubble (the crisis that famously bankrupted Isaac Newton). It is the ultimate exposé on human behavior when blinded by sheer greed.
2. A Random Walk Down Wall Street
Why You Should Read It: This book is the origin of “The Greater Fool Theory” mentioned in our article. Malkiel teaches the fundamentals of stock valuation and explains why attempting to “beat the market” during a bubble is an incredibly dangerous game. It is a masterful blend of financial theory and practical investment strategy.
3. The Big Short: Inside the Doomsday Machine
Why You Should Read It: If you want to visualize the 2008 Subprime Crisis down to the level of “bundled junk,” this is the answer. Lewis tells the story of the few misfits who saw the bubble before anyone else and had the courage to “Short” the market. It is a gripping read that vividly illustrates the systemic rot within the financial world.
4. Manias, Panics, and Crashes: A History of Financial Crises
Why You Should Read It: Widely hailed by economists as the best book ever written on financial crises. It explores how every bubble throughout history shares a similar “DNA,” from the initial expansion of credit (leverage) to the inevitable point where collective rationality completely collapses.
Why You Should Read It: Authored by a Nobel Laureate in Economics who accurately predicted both the Dot-com and Real Estate bubbles. Shiller uses statistical data and psychology to explain how “Irrational Exuberance” is manufactured. This book will help you understand the nuances of the P/E Ratio at a far deeper level than most traders.
