Emotional biases: loss aversion, overconfidence and four more

Why do losses weigh more than gains?

Loss-aversion bias is the strong preference for avoiding losses over achieving gains. People judge outcomes from a reference point, usually the price paid. The pain of a loss is larger than the pleasure of an equal gain: studies are often summarized as a loss feeling about twice as bad as a gain of the same size feels good. Treat the “two” as an illustration, not a number to memorize.

That asymmetry gives a utility curve that is steeper for losses than for gains, and bends in a way that makes people risk-seeking when they are below the reference point and risk-averse above it. A rational investor would accept more risk to increase gains, not to dodge a loss. The loss-averse investor does the opposite. The result is the disposition effect : holding losers too long, in the hope of getting back to even, and selling winners too early, for fear the gain will vanish. The portfolio can end up riskier than the plan intended.

Getting back to even is also harder than it feels. A fall of $L$ needs a larger gain, measured from the lower price.

$$G = \frac{1}{1 - L} - 1 = \frac{L}{1 - L}$$

The adviser’s response: a disciplined approach with sell rules set in advance, and a realistic look at the probabilities of further gains and losses.

The six at a glance

Emotional biasesfeelings and impulses; hard to correct, so adapt

• Loss aversion Memorize losses hurt more than equal gains please
  • Disposition effect sell winners too soon, hold losers too long
• Overconfidence Memorize unwarranted faith in own ability
  • Prediction overconfidence ranges too narrow
  • Certainty overconfidence probabilities too high
  • Illusion of knowledge thinks they know more than they do
  • Self-attribution credit for wins, blame others for losses
• Self-control Memorize short-term satisfaction beats the long-term goal
• Status quo Memorize do nothing; inertia
• Endowment Memorize owning raises the value
• Regret aversion Memorize avoid decisions that may turn out badly
  • Too conservative after a bad risky outcome
  • Herding safer to be with the crowd

Bias	Tell-tale	Consequence	Typical adviser response
Loss aversion	“I will sell when it gets back to even”	disposition effect; may take more risk to avoid a loss	sell disciplines set in advance
Overconfidence	overrates own knowledge or skill	overtrading, under-diversified portfolio, risk underestimated	review trading records for at least two years
Self-control	wants the reward now over the larger later one	saves too little; reaches for risk later; borrows	written plan, budget, strategic asset allocation
Status quo	prefers to leave things as they are	portfolio drifts; unsuitable risk persists	quantify the risk and return benefits of change
Endowment	values what they own above what they would pay	will not sell inherited or familiar assets	“Would you buy this today at this price?”
Regret aversion	avoids acting for fear it will turn out badly	too conservative; herding	show diversification; losses happen to everyone

Overconfidence

Overconfidence bias is unwarranted faith in your own abilities. It has cognitive and emotional elements and is classified as emotional because it results mainly from emotion. Four pieces matter.

• Prediction overconfidence : the confidence intervals around forecasts are too narrow, so the expected variation is too small.
• Certainty overconfidence : the probabilities assigned to outcomes are too high.
• Illusion of knowledge : believing you know more than you do, for example that more information makes forecasts reliable.
• Self-attribution bias : taking credit for successes and blaming others, or bad luck, for failures. It feeds overconfidence.

Consequences: underestimating risk, overestimating returns, overtrading, and poorly diversified portfolios. Active traders have historically earned less than less active investors or the market, at higher risk. The remedy is objective review: list winners and losers over at least two years, ask whether a gain came from analysis or from a rising market, and note patterns in mistakes. “Do not confuse brains with a bull market.”

Self-control, status quo, endowment and regret aversion

Self-control bias is failing to act on long-term goals because of short-term satisfaction. It is linked to hyperbolic discounting, a preference for a small reward now over a larger one later. Saving too little then pushes people to take too much risk in the portfolio to catch up, or to borrow to fund consumption.

Status quo bias is choosing to do nothing even when a change is warranted. Positions are maintained by inertia, not by a decision. A concentrated stock position that quietly grows is a typical case. Showing what happens to total wealth if that stock collapses can motivate a change.

Endowment bias is valuing an asset more because you own it. Standard theory says the price you would pay should equal the price at which you would sell, but sellers name higher prices than buyers. Despite the name, purchased as well as inherited holdings are affected. Ask: “Would you buy this security today at the current price?” or “If you had received the value in cash, how would you invest it?”

Regret-aversion bias is avoiding decisions out of fear they will turn out poorly. It has two sides: errors of commission (actions that were taken and went wrong) and errors of omission (actions that could have been taken but were not). Regret is more intense after an action taken than after one not taken, so doing nothing becomes the default. Results: portfolios that are too conservative after a bad outcome, and herding into popular investments because failing with the crowd feels safer.

Status quo, endowment and regret aversion can all leave positions unchanged, so the reason is the tell.

Positions stay as they arethe outcome is similar; the reason differs

• Status quo Memorize inertia, not a conscious choice
• Endowment Memorize a conscious choice: I own it, so it is worth more
• Regret aversion Memorize a conscious choice: fear of regretting the decision

Read each client scenario, name the bias from its tell-tale, then decide whether the adviser should fight the feeling or plan around it.

Exam tip Find the feeling, name the bias, then decide: moderate or adapt?

Go deeper Prospect theory in one paragraph

Prospect theory describes decisions as gains and losses relative to a reference point, not as final wealth. The value function is S-shaped: steeper for losses than gains, concave for gains (risk-averse) and convex for losses (risk-seeking). That shape explains why an investor with a paper loss may gamble to get back to even, and why a paper gain is locked in early. No formula is needed for the exam, but the shape is the reason behind the disposition effect.

Go deeper Why overconfidence is grouped as emotional

Overconfidence contains faulty reasoning (narrow ranges, ignoring evidence) as well as emotion (pride, hope). The curriculum classifies it as emotional because it mainly results from emotion, but it also notes that more complete information can help correct it. That is why a review of trading records, a cognitive exercise, is a standard remedy.

Go deeper Herding and benchmark hugging

Fund managers can show regret aversion at work: holding what everyone else holds feels safer, because a bad outcome shared with peers is easier to explain than a bad outcome from an unconventional position. Keynes wrote that it is better for reputation to fail conventionally than to succeed unconventionally. The portfolio effect is a preference for well-known companies and for staying close to the benchmark.