Loss Aversion
Money & Trading
Loss aversion is the finding that losses feel roughly twice as powerful as equivalent gains — losing $500 hurts far more than winning $500 feels good, so people go to great lengths to avoid losses.
What it looks like
Most people refuse a fair coin flip that wins $200 or loses $100, even though the bet is mathematically favorable. The pain of the possible loss outweighs the pleasure of the larger possible gain.
It also shows up as the endowment effect: once you own something, giving it up feels like a loss, so you demand more to sell it than you'd ever pay to buy it.
In trading and money decisions
Loss aversion makes traders hold losing positions too long — selling would make the loss real — while cutting winners early to lock in the gain. The result is the classic pattern: small wins, big losses.
It also fuels panic selling at bottoms and reluctance to rebalance, because realizing any loss feels worse than the abstract risk of holding on.
Common questions
- Who discovered loss aversion?
- Daniel Kahneman and Amos Tversky documented loss aversion as part of prospect theory in 1979, showing that people evaluate outcomes as gains and losses relative to a reference point, not as final wealth.
- Is loss aversion rational?
- Avoiding real ruin is rational. Loss aversion becomes a bias when the emotional weight of a loss leads to decisions — like holding a collapsing position — that increase expected losses.
- How do traders manage loss aversion?
- Pre-commit to exit rules before entering a position, size positions so no single loss is emotionally overwhelming, and judge decisions by process quality rather than by whether each one happened to win.
Related biases
- Anchoring BiasAnchoring bias is the tendency to rely too heavily on the first piece of information you encounter — the anchor — when making judgments, even when that number is arbitrary or irrelevant.
- Confirmation BiasConfirmation bias is the tendency to seek out, favor, and remember information that supports what you already believe — while dismissing or never even encountering evidence against it.
- Sunk Cost FallacyThe sunk cost fallacy is continuing an endeavor because of what you've already invested — money, time, effort — rather than because of what lies ahead. Sunk costs are gone; only future costs and benefits should matter.
Check your own reasoning
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