The Endowment Effect: People Overvalue What They Own
Behavioral economics research, formalized by Richard Thaler · Kahneman, Knetsch, and Thaler (1990) 'Experimental Tests of the Endowment Effect' (1990)
The endowment effect is the cognitive bias where people ascribe more value to things merely because they own them, leading to irrational decision-making in market exchanges and investment choices.
Core Concepts
The Problem
Ownership creates an emotional attachment that overrides objective assessment of an asset's true value.
The Claim
Individuals demand much more to give up an object than they would be willing to pay to acquire it, creating a gap between buying and selling prices.
Key Evidence
- •Kahneman et al. (1990) mug experiments: participants demanded seller prices often double the buyer prices.
- •Numerous replications in stock trading showing investors hold onto losing positions longer than rational models predict.
Practical Implication
Traders and investors often refuse to sell losing positions or overvalue their own holdings, leading to suboptimal portfolio outcomes.
Nuance & Limits
The effect is weaker for traded goods where substitutes exist and stronger for unique or sentimental items. Market experience can reduce but not eliminate it.
Source Material
Citation Density
Extensively cited (>5000 citations across economics and psychology)
Gaps
- ⚠ The neural mechanisms are still being studied.
- ⚠ Cultural variation in the effect is not fully understood.
Who's Talking About This
1 episode reference this idea.
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