Bull runs can make investing feel easy: prices rise, portfolios turn green and success stories spread. Yet individual investors can still lose money by entering late, taking excessive risk or letting the excitement overwhelm judgment.
That would never occur if markets were entirely rational. Fundamentals would rule to set prices, investors buy low and sell high, and everyone goes away happy. Markets, however, are not run by robots. They are operated by people; people bring bias, emotions, and blind spots that quietly undermine the best of intentions.
Understanding behavioral biases helps explain how investors can give back gains even during favorable markets. Four recurring forces are fear of missing out, overconfidence, the disposition effect and anchoring.
FOMO and the Trap of the Herd Mentality
Fear of missing out is right up there with the best of them for powering that awful decision-making. If a market is heating up, timelines explode with stories of success, images of accounts that skyrocketed overnight are plastered everywhere, and the noise becomes deafening. All of a sudden, sitting on the sidelines starts to look like the biggest gamble – you know, the safest play in most circumstances.
Herd behavior draws people toward decisions that appear socially validated. Seeing others profit can make an investment feel attractive before its risks have been examined.
A bull market can reward risk-taking temporarily without proving that every decision was sound.
Urgency can drown out the question of whether a large recent rise has already priced in the optimism.
By the time an asset dominates conversation, earlier holders may already be positioned to sell. Popularity does not reveal whether the current price offers a reasonable opportunity.
Rising prices attract attention, new buying pushes prices higher and the cycle reinforces itself. When buying demand weakens, the same crowd may rush to sell, intensifying a decline.
Investor.gov offers FOMO guidance encouraging readers to resist pressure from popular trends and endorsements.
Separating research from social pressure creates useful friction. Ask whether the investment would still be attractive if nobody were discussing it, and whether the decision rests on evidence or excitement.
Overconfidence Bias During Rising Markets
A run of gains can create the impression that profitable outcomes demonstrate skill. In a broad rally, many decisions benefit from the same favorable conditions, making it easy to overestimate personal judgment.
A few profitable trades can encourage larger positions, reduced diversification and neglected risk limits. A favorable market can make those changes look sensible until conditions reverse.
The lesson is that overconfidence is the most dangerous when it seems the most warranted. The investors who, for the most part, were prudent and slow with their decisions when things turned cloudy throw caution to the winds once they’ve found a little success. Their trading volumes ramp up considerably to chase riskier assets and start exhibiting warning signs that, under different circumstances, they would have been far more cautious about.
The hot-hand fallacy can lead investors to treat a streak of gains as evidence that the next trade will also work. Outcomes in a rising market may reflect shared conditions rather than enduring skill.
Exit liquidity helps explain why late enthusiasm can benefit earlier sellers.
Overconfidence isn’t rewarded forever in bull markets. Over time, however, market conditions change, and the same forceful positioning that created outsized gains on the way up can create outsized losses on the way down. Investors who do the best over a long period of time are often those who remain skeptical about their own success, and just keep applying the same discipline/risk controls regardless of how well things are going right now.
The Disposition Effect: Selling Winners and Holding Losers
The disposition effect describes a tendency to realize gains readily while resisting the sale of losing positions. Emotional comfort can displace an assessment of future prospects.
The psychology behind this trend is very deep. When a holding is performing well, it produces an internal voice that screams “lock in” before the wind blows and changes everything. Even a small profit feels good, and the fear of seeing that profit diminish is usually stronger than the hope that it will keep growing. Thus investors exit early, often leaving a significant amount of upside uncapitalized.
Selling a loser means accepting a loss, which can feel like admitting a mistake. Loss aversion helps explain that reluctance, but the impact varies and should not be reduced to a universal numerical rule.
The by-product is a composite that does precisely the opposite of what sound investing recommends. Investors cut the winners and let losses run instead of cutting losses and letting the winners run. You close out small profitable positions, only to hold on indefinitely to assets that are leading you down the wrong road or do not have great underlying fundamentals, thus blocking capital from potentially being used more advantageously.
This can be detrimental, especially during bull runs. In other words, early sellers of winners miss most of a rally, but stagnant (or worse) capital in low-growth positions is left with zero opportunity to benefit from the updraft. This means that when the lost position is eventually offloaded near the bottom of a downswing, often immense opportunity cost really begins to add up.
In order to break this pattern, the mindset must change: every position should be assessed on its own merits today and into the future, not based on how much was paid for it. The price at which you bought an asset is not relevant to whether that asset ought to be for sale today. Outcomes are less important than whether the rationale for owning it is still intact.
Anchoring and Unrealistic Price Expectations
Anchoring is the tendency to rely too heavily on one reference point, such as a past price, when making a decision. That reference may be poorly connected to present conditions.
In crypto and stock markets alike, this often shows up in two ways. First, investors anchor to an asset’s all-time high. If a coin once traded at a certain peak, that number becomes lodged in memory as the “real” value, and any price below it feels like a discount, regardless of whether the fundamentals or market conditions that justified that peak still exist. This leads to buying decisions based on the assumption that the asset simply must return to its former glory, rather than an honest assessment of whether it can or should.
Second, investors anchor to their own entry price. Once someone buys an asset at, say, a certain dollar amount, that number becomes an emotional marker. If the price falls below it, there’s a strong urge to hold on until it “breaks even,” even if better opportunities exist elsewhere. If the price rises above it, the original entry point still influences decision-making, sometimes causing investors to sell too early simply because they’re already “in profit” relative to that anchor.
Being late to crypto narratives can magnify the effect of social pressure on timing.
Bold forecasts and social-media predictions can provide new anchors during a bull run. Investors may begin treating an unsupported target as an expected destination rather than one uncertain scenario.
Markets do not have to return to a former price or meet a public prediction. Decisions based on outdated reference points can lag changes in demand, liquidity and economic conditions.
Combating anchoring bias starts with actively questioning the source of any price target or expectation. Is a belief based on independent research and market conditions, or is it based on a chart from six months ago, an entry price, or a bold claim from someone with an incentive to hype the asset?
Conclusion
Bull runs place psychology under pressure. FOMO can encourage late entries, favorable outcomes can foster overconfidence, and the disposition effect can keep weak positions in a portfolio.
Anchoring can keep an investor focused on an entry price or former high instead of current evidence.
None of these patterns are signs of poor intelligence. They’re deeply human responses, hardwired into how people process risk, reward, and social pressure. That’s precisely what makes them so dangerous: they don’t feel like mistakes while they’re happening. They feel like instinct, conviction, or common sense.
Investors can build processes that account for these tendencies through clear objectives, exposure limits and regular reassessment. Awareness helps, but does not eliminate losses.
Bull markets will keep coming, and so will the emotional pull that comes with them. But recognizing these four psychological patterns is a powerful first step toward making decisions based on strategy rather than sentiment, and toward keeping more of the gains that bull runs are supposed to deliver in the first place.
Frequently Asked Questions
Why can investors lose money in a bull market?
They may enter late, take excessive risk, overtrade or fail to reassess positions when conditions change. Rising market averages do not protect every portfolio.
What is the disposition effect?
It is the tendency to realize gains readily while resisting the sale of losing investments. Emotional attachment can replace an assessment of current prospects.
How does anchoring affect crypto decisions?
An entry price or former high can become a reference point even when circumstances change. That reference does not determine an asset’s future value.
