How Bubbles Start With Herding
How Bubbles Start With Herding
Asset price bubbles begin not with market crashes or systemic failures but with modest price appreciation that attracts attention and triggers early herding behavior. A company releases strong earnings; investors buy the stock; the stock rises and attracts additional investors; these new investors buy partly due to fundamental analysis and partly due to herding psychology. The herding component, seemingly minor at first, becomes increasingly dominant as prices rise. Eventually, herding becomes the primary driver of prices, fundamentals become irrelevant to purchasing decisions, and the market has transitioned from overvaluation to bubble-level disconnection from reality. Understanding how bubbles originate in the early stages of herding behavior allows investors to recognize bubbles while they are forming and avoid entry at prices least likely to be recovered. Every financial bubble in history shares this pattern: legitimate initial price increases that gradually become dominated by herding behavior, self-reinforcing until the crowd's psychology suddenly reverses and prices collapse with violence proportional to the prior herding intensity.
Quick definition: Bubble formation occurs when herding behavior transforms an initial legitimate price increase into sustained buying driven primarily by crowd psychology rather than fundamental value, creating disconnection between price and intrinsic worth.
Key takeaways
- Bubbles begin with legitimate price increases and fundamental reasons for valuation expansion before herding dynamics take over
- Early herding attracts observers who interpret visible momentum as evidence of market wisdom and join the buying
- Self-reinforcing feedback loops develop where rising prices attract herding capital, which lifts prices further, attracting additional herders
- Fundamental analysis becomes displaced by narrative-based thinking as bubbles mature and herding dominates pricing
- Recognizing early-stage herding characteristics allows investors to exit bubble positions before final-stage collapse
The anatomy of bubble formation
Bubbles follow a consistent pattern across different eras and asset classes. The pattern begins when a legitimate catalyst provides genuine reasons for price appreciation. In the 1990s technology bubble, the catalyst was the emergence of the Internet as a transformative technology. In the mid-2000s housing bubble, the catalyst was genuine financial innovation in securitization and sustained increases in real estate valuations. In the 2017-2021 cryptocurrency boom, the catalyst was adoption of blockchain technology and the vision of decentralized finance. These catalysts are real; the investment opportunity they present is often genuine.
During the initial phase of the bubble, legitimate investors with genuine conviction in the catalyst begin purchasing. Technology fund managers invest in promising internet companies based on thorough analysis of competitive advantages and market opportunities. Housing investors purchase mortgage securities based on reasonable assumptions about underwriting and the historical stability of housing prices. Cryptocurrency developers and early adopters invest in projects based on genuine belief in technological innovation. This early buying drives modest price appreciation.
The modest price appreciation attracts attention from investors with less expertise and lower conviction. These secondary-wave investors observe that smart people are already invested in the asset class and that prices are rising. Herding instincts activate: if smart people are buying and prices are rising, perhaps the opportunity is real. These secondary-wave investors conduct less rigorous analysis than the first wave; they rely more heavily on social proof (others are buying) and momentum (prices are rising). Yet their capital has real purchasing power, so their herding behavior further lifts prices.
Rising prices provide visible confirmation that the original thesis was correct. The price appreciation becomes self-reinforcing: higher prices attract more herding investors, who attribute the price appreciation to market wisdom about the asset's value. These newer investors purchase despite uncertainty about fundamentals, assuming that market prices incorporate superior collective knowledge. The herding wave intensifies with each successive price increase.
The role of narrative and story in bubble dynamics
Bubbles thrive on narratives—compelling stories about why traditional valuation metrics no longer apply and why the old rules are being replaced by new paradigms. In the technology bubble, the narrative was "the Internet will transform all commerce and communication, so traditional earnings metrics do not apply to Internet companies." In the housing bubble, the narrative was "housing prices never decline nationally and securitization has eliminated risk from mortgages." In the cryptocurrency bubble, narratives range from "blockchain will replace traditional financial systems" to "digital scarcity creates inherent value independent of utility."
These narratives are often rooted in partial truths. The Internet did transform commerce and communication. Housing prices have historically appreciated in the long run. Blockchain technology is genuine innovation. However, bubbles occur when the narrative becomes disconnected from the pace of implementation or when investors begin using the narrative to justify prices that exceed any reasonable projection of fundamental value.
As herding dominates the bubble, narrative thinking replaces fundamental analysis. An investor in a bubble is less likely to think, "Company X will generate 15% annual earnings growth and deserves a 20 times P/E multiple," and more likely to think, "This company is in the Internet space and Internet companies are changing the world, so I should own it." The narrative becomes sufficient justification for purchase. Investors stop asking whether prices are justified by fundamentals and instead ask whether the narrative remains persuasive to the crowd.
How herding amplification creates bubble conditions
The mechanism through which herding creates bubble conditions involves several reinforcing feedback loops. First, rising prices attract additional herding investors, whose buying further elevates prices. This feedback loop is self-sustaining as long as new capital continues entering the market.
Second, rising prices attract media coverage and broker recommendations, which amplify the visibility of the trend and attract retail investors. By the bubble's later stages, every financial publication features stories about the surging asset class. Brokers issue positive research. Financial news shows highlight investors who profited early. This media amplification accelerates herding by reaching investors with limited financial expertise and minimal prior interest in the asset class.
Third, rising prices create wealth effects that fuel additional buying. Early investors in a bubble experience substantial unrealized gains. These paper profits create psychological wealth effects—the sensation of having become wealthy despite unchanged employment income. This sensation triggers increased spending and increased investment risk appetite. The early investors often plow profits from other investments into the bubbling asset class, adding additional herding capital.
Fourth, rising prices lower the perceived risk of investment. When a stock that an investor bought at $20 rises to $50, the $50 purchase price feels safer than the $20 price would have, because the crowd of investors who bought at intermediate prices ($30, $40) have profited. This collection of profit-takers creates a coalition psychologically supportive of the investment. An investor buying at $50 observes thousands of people who bought between $20 and $50 and all are profitable. This observation triggers herding instinct: if this many people are profitable, surely the investment is sound.
This mechanism—lower prices feeling riskier than higher prices in a bubble context—inverts normal risk assessment. In reality, buying at $50 after a $30 appreciation is riskier than buying at $20. Yet the herding psychology creates the opposite perception. This inversion makes bubbles self-accelerating during their growth phases.
The transition from herd-driven appreciation to bubble dynamics
The transition from legitimate herding based on genuine interest to speculative bubble occurs gradually and without obvious inflection point. Typically, the transition is identifiable in retrospect but difficult to perceive in real time. The key distinction lies in the disconnect between prices and reasonable projections of future cash flows or fundamental value.
Consider the technology bubble: legitimate reasons existed in 1995-1997 for technology stocks to outperform. The Internet was transforming commerce and communication. Companies with superior technology and large addressable markets deserved premium valuations. Technology stocks appreciated from undervalued 1994 levels to fairly valued levels by 1997, and this appreciation was justified by improving fundamentals.
However, by 1999, technology valuations had expanded to levels where even aggressive optimistic projections about future profits could not justify current prices. A company trading at 100 times forward earnings with no current profits would require implausible future growth to justify the valuation. Yet herding investors purchased not because they believed in the implausible projections but because prices were rising and others were buying. The herding had become decoupled from fundamentals. The market had transitioned to bubble phase.
Identifying bubbles while they are forming
Investors who can identify bubbles while they are forming gain significant advantages: they can avoid entry at peak prices, exit positions before declines, and position for the eventual reversion. Several characteristics distinguish bubble-phase herding from legitimate appreciation:
Valuation metrics become extreme. In bubbles, traditional valuation measures reach levels that are extreme by historical standards. Price-to-earnings ratios for entire sectors exceed anything observed in prior decades. Price-to-sales ratios for companies with minimal revenue reach absurd levels. These metrics alone do not prove a bubble (metrics can be justified by exceptional growth assumptions), but extreme valuations should trigger higher scrutiny.
Narrative-based reasoning dominates analyst commentary. Analysts discussing bubble assets often rely on stories about market transformation and paradigm shifts rather than concrete projections of cash flows and earnings. Phrases like "the old rules no longer apply" and "this is different this time" become common. Analyst research reports lack specific numerical forecasts and instead contain expansive narratives about long-term possibilities.
Retail investor participation expands dramatically. Bubbles intensify as they attract retail investors with limited investment experience and minimal prior interest in the asset class. Brokerage account openings, trading volume in bubble assets, and social media discussion of bubble assets expand exponentially during the final phases. The presence of large populations of retail investors making purchases based on social proof rather than analysis indicates that herding has become dominant.
Price momentum becomes the primary buying thesis. In later-stage bubbles, investors openly state that they are buying because prices are rising and other people are buying. Justification for entry shifts from "this company has strong competitive advantages" to "this stock is up 200% so it will probably continue rising." The explicit admission that buying is momentum-based reveals that herding has replaced analysis.
Contrary analysis is dismissed as outdated or ignorant. In bubbles, skeptics are not engaged with rational counter-arguments but are instead dismissed as people who "do not understand the new paradigm" or lack sufficient sophistication to perceive the opportunity. This dismissal of dissent indicates groupthink and herding rather than intellectual confidence based on analysis. Genuine intellectual conviction tolerates and engages with contrary views; herding psychology requires suppressing doubt and dismissing doubt-sources.
The timing challenge of bubble identification
A significant challenge in identifying bubbles while they form lies in the genuine difficulty of timing reversals. A bubble may be identifiable as overvalued based on fundamental analysis, but overvaluation can persist for extended periods while herding continues driving prices higher. An investor who identifies a bubble at 50% overvaluation might hold the position through further 100% appreciation while waiting for the reversal.
The housing market before 2008 provides illustration. Academics and analysts raised legitimate concerns about housing valuations beginning in 2003-2004. Some investors began shorting housing-related securities as early as 2005. Yet housing prices continued appreciating for two additional years before the market peaked in 2006-2007. Investors with correct fundamental analysis about housing overvaluation nonetheless suffered losses if they bet against the market too early. The herding dynamics sustained the bubble longer than fundamental analysis would predict.
This timing challenge means that identifying a bubble correctly still requires discipline about when to act on that identification. The best practice combines fundamental analysis identifying overvaluation with momentum analysis recognizing when momentum is weakening. Sell signals emerge not merely from overvaluation identification but from momentum divergence—when rising prices no longer attract fresh herding capital and momentum begins slowing.
The collapse phase and herding reversal
Bubbles collapse not because of new information proving that the asset is worthless (typically the asset retains genuine value despite bubble-level pricing) but because herding reversal occurs. Some catalyst—a disappointing earnings report, a prominent investor exit, a media story highlighting overvaluation, or simply fade in herd enthusiasm—triggers the initial momentum reversal. This reversal need not be large; a modest reversal is sufficient to change the herding dynamic.
When prices begin declining and the uptrend breaks, the herding crowd that participated in the rise now observes a negative momentum signal. To herding investors, declining prices are evidence that the opportunity has disappeared. The herd attempts to exit simultaneously. Selling accelerates. Prices decline further. The same psychological mechanism that created self-reinforcing price increases now creates self-reinforcing price decreases. Herding that amplified upward momentum now amplifies downward momentum.
The final-stage collapse of a bubble is often sharp and severe—prices decline 50%, 70%, or 80% from peak levels—because the herding crowd exits all at once rather than gradually. The early buyers, who understood fundamentals and had conviction, exited higher during the appreciation phase. The late buyers, who participated primarily due to herding and social proof, are forced to exit during the collapse, realizing losses.
Summary
Bubbles originate in legitimate price appreciation driven by genuine catalysts and early investors with conviction. As prices rise, herding behavior amplifies the appreciation, attracting secondary waves of investors who rely on social proof and momentum rather than analysis. Self-reinforcing feedback loops develop where rising prices attract herding capital, which further elevates prices, which attracts additional herding. Eventually, herding becomes the dominant pricing driver and prices become disconnected from fundamentals. Identifying bubbles involves recognizing extreme valuations, dominance of narrative-based reasoning, explosive retail investor participation, and dismissal of contrary analysis. Bubbles collapse when herding reversal occurs and the crowd attempts to exit simultaneously, causing sharp declines proportional to the herding intensity during the rise. Understanding how herding initiates bubbles allows investors to avoid entry at overvalued levels and exit positions before reversals.