What Is the Endowment Effect? Why We Overvalue What We Own

You decide to sell a sofa you have had for years. It is worn, a little faded and the same model sells second-hand for £150. Yet when the first buyer offers £120, you feel insulted. To you it is surely worth more, though you would never pay £200 for one like it.

That gap between what we would pay for something and what we demand to give it up is the endowment effect.

What is the endowment effect?

The endowment effect is the tendency to value an object more highly once we own it. The term was coined by economist Richard Thaler in 1980 to describe a puzzle: people often demand much more to sell something than they would have paid to buy it, which is not what standard economic theory predicts. It is a close relative of the IKEA effect, where effort adds to value, and the sunk cost fallacy, where past investment locks us in.

The classic experiments

In a famous set of studies, Daniel Kahneman, Jack Knetsch and Richard Thaler randomly gave some students a university-branded coffee mug and not others. Those who received the mug were then asked the lowest price at which they would sell; those without one were asked the most they would pay. The median selling price was about twice the median buying price, roughly $7 against $3. A control group with no ownership showed that the mugs were not simply more valuable to the people who got them, because the owners’ values were not different at the outset. Mere ownership made the difference.

Later studies found similar patterns with pens, chocolate, tickets and many other goods.

Why does it happen?

Loss aversion

The most common explanation links the effect to loss aversion: losing something hurts more than gaining the same thing feels good. For an owner, selling feels like a loss. For a potential buyer, paying feels like a smaller loss of money. See what is the framing effect for the research on gains and losses.

Attachment and identity

Once an item is ours it becomes part of our story. We attach memories and a sense of self to it, which pushes the value up.

Reference points

Ownership shifts our reference point: what we have feels like the baseline, and any move away from it feels like a loss.

Ownership and attention

Researchers such as Carey Morewedge and Colleen Giblin review several explanations, including how ownership changes what we notice about an item, its positive features and not its flaws, and the pain of the exchange itself.

The debate

Not all researchers agree on how general or large the effect is. Charles Plott and Kathryn Zeiler found that when participants were given thorough training and anonymity in how valuations were elicited, the gap between buying and selling prices shrank or disappeared, suggesting that part of the original finding came from how experiments were set up. Others have found the gap is stronger for items “held for use” than for those held for exchange, such as cash or tokens, and is influenced by experience: seasoned traders show a smaller effect.

The sensible summary is that ownership often inflates value, particularly for things with personal meaning, but the size depends on context.

Everyday examples

• Selling a car or home: owners set asking prices above market value.
• Keeping clutter: you hold on to clothes you never wear because they are yours.
• Investing: investors cling to shares they own, even when better options exist.
• Free trials: a month of using a product makes it harder to give up, which companies exploit.
• Gifts: we often value a gift more than its price suggests.
• Ideas and opinions: we can feel attached to our own plans and arguments.
• Relationships and jobs: sometimes we stay because leaving feels like a loss.

How to value things more fairly

1. Ask the “would I buy it?” question

Imagine that you did not own the item and had to buy it today at the asking price. Would you? If not, its value to you may be inflated.

2. Check market prices

Look at what similar items actually sell for, not what listings ask. Comparable sales cut through sentiment.

3. Sell in your head first

Imagine the item sold, and picture the life afterwards. Often the loss seems smaller once you have rehearsed it.

4. Set selling rules in advance

Decide a price or a time limit before listing, such as “if no one pays £100 in a month, I drop it to £80.” Rules protect you from drifting attachments.

5. Separate memories from objects

Photograph the item or write down what it means to you, and let it go. Memories live in you, not in the object.

6. Declutter with a trial

Put items in a box for three months. If you do not reach for them, release them.

7. Use the effect on purpose

If you are trying to value your own work or time, remember that you may overvalue it too, and seek an outside opinion.

A worked example

Marta wants to sell her flat and is annoyed by offers 7 percent below her asking price.

1. Would I buy it? She asks herself whether she would pay her asking price for an equivalent flat. She is not sure.
2. Market check: she looks at the sold prices of three similar flats in the same building, all near the offers.
3. Sell in her head: she imagines living in her next home and feels more relaxed.
4. Rule: she decides that she will accept any offer within 3 percent of the recent comparable sales.
5. Memories: she photographs the balcony she loves.

She sells within a month at a price she is comfortable with.

Common mistakes

• Treating your valuation as the market price. Check the market.
• Anchoring on what you paid. It is irrelevant to current value. See what is the anchoring bias.
• Believing you are immune. Experts show it too.
• Holding on until value falls. Delay can cost you.
• Confusing sentimental value with market value. Both are real but different.

Frequently asked questions

What is the endowment effect in simple terms?

We value things more once we own them, so we demand more to give something up than we would pay to get it.

Who discovered the endowment effect?

Richard Thaler named it in 1980, and Kahneman, Knetsch and Thaler tested it in their 1990 mug experiments.

Is the endowment effect the same as loss aversion?

They are related. Loss aversion is a common explanation, but researchers debate whether it fully accounts for the effect.

Is the endowment effect always strong?

No. It varies with the type of item, experience and how valuations are measured, and some studies find a much smaller gap.

How can I avoid the endowment effect when selling?

Check market prices, imagine buying the item fresh and set selling rules in advance.

How do companies use the endowment effect?

Through free trials, returns policies and virtual try-ons that create a sense of ownership before you pay.

The bottom line

Ownership quietly raises the price tag in our minds. Imagine you did not own it, check real market prices, set rules in advance and let go of the memory without the object. A fairer valuation helps you sell, declutter and decide with a clearer head.