Common Behavioral Biases and Financial Decision-Making

Updated for the 2026-2027 CFA® Level I curriculum.

Investors don't always act on logic. Behavioral biases in investing push decisions away from rational analysis toward habit, emotion, or flawed reasoning. CFA Level I tests whether you can recognize a specific bias in an investor scenario and match it to the decision error it causes. This note groups the ten most testable biases by the mistake they produce, not by definition alone.

Key Takeaways About Common Behavioral Biases and Financial Decision-Making

• Behavioral biases split into two groups: cognitive errors (reasoning-based) and emotional biases (feeling-based), and Level I expects you to classify each one correctly.

• Cognitive errors respond to better information, checklists, or a second opinion because the root problem is faulty processing.

• Emotional biases resist full correction. Advisors usually accommodate them with structure instead of trying to eliminate them.

• Overconfidence, loss aversion, endowment, status quo, and regret aversion are the emotional biases in this note.

• Confirmation, conservatism, anchoring, framing, and availability are the cognitive biases in this note.

• The exam rewards linking a bias to the exact decision error it produces, not just naming the term.

What You Need to Know for CFA Level I

• Know the definition and category, cognitive or emotional, for all ten biases covered here.

• Recognize each bias from a short investor scenario, not only from a memorized definition.

• Separate overconfidence from hindsight bias. Overconfidence overstates current judgment; hindsight bias distorts memory of a past prediction.

• Understand that cognitive errors are corrected with information while emotional biases are usually accommodated.

• Apply the correct response, correction or accommodation, when a question asks what an advisor should do.

• Expect one or two questions per exam that test bias identification in a client scenario.

What Are Behavioral Biases in Investing?

Traditional finance assumes investors process information objectively and choose the option that maximizes expected value. Behavioral finance shows that real investors let mental shortcuts, habits, and emotions shape decisions instead. A behavioral bias is a repeatable pattern in that deviation, not a one-time mistake.

Cognitive Errors vs Emotional Biases

This note focuses on the ten specific biases tested at Level I. For a deeper look at why the two categories are corrected differently, see Cognitive Errors vs Emotional Biases.

Biases That Inflate Confidence in Judgment

Overconfidence bias (emotional)

Investors overestimate the accuracy of their own forecasts and abilities. This leads to overtrading, under-diversification, and underestimating risk.

Confirmation bias (cognitive)

Investors seek information that supports an existing view and ignore evidence that contradicts it. This leads to concentrated positions and slow reactions to bad news.

Availability bias (cognitive)

Investors weight easily recalled information, such as recent headlines or memorable events, more heavily than complete data. This leads to distorted risk assessment based on vivid but unrepresentative examples.

Biases That Resist New Information

Conservatism bias (cognitive)

Investors underreact to new information and cling to prior views or forecasts. This delays portfolio adjustments after material news.

Anchoring and adjustment bias (cognitive)

Investors fixate on an initial reference point, such as a purchase price, and adjust insufficiently away from it. This causes investors to hold a losing position because the original price feels like the "true" value.

Bias That Distorts How Choices Are Presented

Framing bias (cognitive)

Investors make different decisions depending on how the same choice is worded, such as framing an outcome as a gain versus a loss. This produces inconsistent risk-taking based on phrasing rather than the actual economics of the decision.

Biases That Create Inertia and Avoidance

Status quo bias (emotional)

Investors prefer to keep existing holdings rather than make a change, even when a change would improve the portfolio. This leads to outdated allocations and unaddressed concentration risk.

Endowment bias (emotional)

Investors value an asset more once they own it, often from familiarity or sentiment. This causes reluctance to sell inherited or long-held positions even when they no longer fit the plan.

Regret aversion bias (emotional)

Investors avoid taking action to avoid the possible regret of a bad outcome. This produces excessive conservatism, such as staying in cash or resisting necessary rebalancing.

Bias That Distorts Risk Perception Around Gains and Losses

Loss aversion bias (emotional)

Investors feel the pain of a loss more strongly than the pleasure of an equivalent gain. This causes investors to hold losing positions too long and sell winning positions too early, a pattern known as the disposition effect.

Behavioral Bias Comparison Matrix

The table below summarizes all ten biases in one place. Use it as a quick reference before practice questions, not as a substitute for understanding the decision error behind each bias.

Worked Example

Scenario. Rania inherited stock in her father's former employer 15 years ago. The stock has underperformed the market for five straight years, but she refuses to sell, saying "it's been in the family, and it will come back." She also skips reviewing quarterly reports because she is confident the company will recover.

Tom bought a technology stock at $120 per share. It has since fallen to $70. He insists the stock is still worth $120 because that is what he paid. When his advisor shows him a report on a product recall, Tom dismisses it as biased and points to two blog posts that support his original view.

Step 1: Identify Rania's biases

Endowment bias, because she values the stock more due to family attachment. Status quo bias, because she avoids reviewing or changing the position.

Step 2: Identify Tom's biases

Anchoring and adjustment bias, because he fixates on the $120 purchase price as the "true" value. Confirmation bias, because he seeks sources that support his view and dismisses the negative report.

Step 3: Match the response to the bias type

Rania's biases are emotional, so the advisor accommodates them. This might mean a mandatory annual review paired with a gradual, tax-aware diversification plan that respects her attachment while limiting concentration risk.

Tom's biases are cognitive, so the advisor corrects them. This means presenting an objective valuation that ignores the purchase price and requiring a review of balanced sources, including the negative report.

Emotional biases like Rania's are worked around, not eliminated. Cognitive biases like Tom's often respond to structured logic and objective information. The exam tests whether you know which approach fits which bias type.

Common Exam Traps

Naming a bias without linking it to behavior

Questions reward identifying the specific action the bias causes, not just labeling the term correctly.

Confusing overconfidence vs hindsight bias

Hindsight bias distorts memory of a past prediction, shown by statements like "I knew it all along." Overconfidence overstates the accuracy of current judgment. They often appear in the same scenario but test different reasoning.

Assuming all mitigation is education

Cognitive errors improve with information and structured checklists. Emotional biases usually need accommodation, such as automatic rules or predetermined limits, because education alone rarely changes them.

Forgetting that accommodation is a valid exam answer

Some questions test whether a candidate wrongly tries to "correct" an emotional bias when the better answer is to build a process around it instead.

Practice Question

An investor bought a mutual fund three years ago and has not reviewed the holding since, despite underperformance against its benchmark every year. When his advisor suggests switching funds, he says he would rather keep things as they are because reviewing new options feels like too much effort. This behavior is best described as which bias?

1. Confirmation bias

2. Status quo bias

3. Regret aversion bias

FAQs About Common Behavioral Biases and Financial Decision-Making