Block R · Behavioral finance
‹ Financial markets handbook: overview
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The most expensive mistakes are made not in the market but in the head; behavioral finance catalogs them; the benefit lies in counter-rules, not in knowledge alone.
201 · Loss aversion & disposition effect
Definition: Losses hurt ~2x more than equal gains please; the consequence: selling winners too early, holding losers too long (disposition effect).
Practical consequence: Portfolios accumulate "hope positions"; tax logic (realize losses!) is ignored.
Counter-rule: Regularly ask each position: "Would I buy this today?"; if not, the purchase price is irrelevant.
Typical mistake: The purchase price as the anchor for holding/selling.
See also: 205 · Countermeasures: investment guidelines · 162 · Drawdown management & stop-loss logic
202 · Overconfidence & home bias
Definition: Systematic self-overestimation (hit rate, knowledge) and overweighting the home market as perceived safety.
Practical consequence: Too much trading (costs!), too little global diversification; German portfolios notoriously DAX-heavy.
Counter-rule: Log trades and measure the hit rate; world market weights as the reference for the equity allocation.
Typical mistake: Confusing familiarity ("I know it") with safety; see concentration risk 156.
203 · Herding
Definition: Orienting oneself by the behavior of the crowd, amplified by media and performance rankings; feeds bubbles and panic.
Practical consequence: Inflows at the high, outflows at the low; the "behavior gap" between fund and investor return.
Counter-rule: Countercyclical automation (rebalancing, savings plans); rationing news consumption in crises.
Typical mistake: Reading consensus as safety; when everyone is invested, the next buyer is missing.
204 · Anchoring & framing
Definition: First numbers (purchase price, all-time high, price target) act as anchors; the presentation frame (framing) steers decisions ("90% chance of gain" vs. "10% risk of loss").
Practical consequence: "I will sell when I am back at zero"; products are sold via framing (the coupon optics of certificates).
Counter-rule: Formulate decisions prospectively (target prices from valuation, not from cost basis); check numbers in both frames.
Typical mistake: Viewing the all-time high as a "fair value" to which the price "must return".
205 · Countermeasures: investment guidelines, rebalancing, rule-based investing
Definition: Institutionalized self-commitment: written investment guidelines (144), automatic rebalancing (143), checklists, a decision journal, the four-eyes principle.
Practical consequence: Behavior becomes the largest controllable "return source"; the behavior gap costs 1-2% p.a. depending on the study.
Counter-rule: Adopt rules in calm times and do NOT renegotiate them in stress phases.
Typical mistake: Relying on discipline in the emergency instead of on processes built in advance.
See also: 144 · Risk profiles & investment guidelines · 143 · Rebalancing · 201 · Loss aversion & disposition effect