The Disposition Effect: Why Investors Sell Winners and Hoard Losers

You bought a stock at $50. It's now worth $35. You don't sell — because selling would mean admitting you were wrong, locking in the loss, making it real. Meanwhile, another stock in your portfolio climbed from $50 to $68. You sell it quickly to "lock in the gains" before something goes wrong. Congratulations: you just demonstrated the disposition effect. You held the loser, sold the winner, and did the opposite of what the evidence suggests leads to good investment returns.

Naming the Pattern

The disposition effect was formally identified and named by economists Hersh Shefrin and Meir Statman in their landmark 1985 paper "The Disposition to Sell Winners Too Early and Ride Losers Too Long: Theory and Evidence," published in The Journal of Finance. The name captures the phenomenon precisely: investors are "disposed" to realise gains quickly and defer realising losses — the disposition to sell, or not to sell, is systematically distorted by whether the position is currently profitable.

Shefrin and Statman grounded their analysis in the prospect theory of Daniel Kahneman and Amos Tversky (1979). Prospect theory describes how people evaluate outcomes relative to a reference point (typically the purchase price), and features two key asymmetries. First, losses feel roughly twice as painful as equivalent gains feel pleasurable — this is loss aversion. Second, the utility function is concave in the gains domain and convex in the loss domain, meaning people are risk-averse when ahead (willing to take a certain smaller gain rather than gamble for more) and risk-seeking when behind (willing to gamble to avoid a certain loss). Together, these features predict exactly the disposition effect: sell winners (risk-averse in gains), hold losers (risk-seeking in losses, hoping to "get back to even").

The Evidence

The empirical record on the disposition effect is unusually robust. Terrance Odean's 1998 analysis of 10,000 brokerage accounts at a large discount broker — one of the most cited papers in behavioural finance — found that investors were 50% more likely to sell a winning position than a losing one, controlling for other factors. This held across calendar months, income levels, and portfolio sizes. The effect was persistent and pervasive.

Crucially, Odean also showed that the stocks investors sold (the winners) subsequently outperformed the stocks they held (the losers), on average. Selling winners and holding losers wasn't just psychologically driven — it was actively harmful. Over the subsequent year, the sold winners outperformed the held losers by roughly 3.4 percentage points. Investors were systematically selling the better assets and keeping the worse ones.

The effect has since been replicated in futures markets, real estate transactions, mutual fund manager behaviour, and even experimental asset markets with incentivised participants. It appears in professional traders as well as amateurs, though its magnitude varies. It is one of the most reliably documented systematic errors in human economic behaviour.

"I'll Sell When It Gets Back to Where I Bought It"

The most emblematic expression of the disposition effect is the investor's refrain: "I'll sell when it gets back to where I bought it." This statement reveals the psychology precisely. The purchase price has become a reference point — a psychological anchor — and the investor cannot bring themselves to sell below it, because doing so would crystallise the loss. Above that reference point, the gain is real and present and pleasurable; below it, the loss is painful and to be avoided by keeping the position open.

But the purchase price is a sunk cost. It is economically irrelevant to the question of whether to hold or sell the asset today. The question that matters is: given the current price and current information, would I buy this asset at its current valuation? If the answer is no — if you would not buy the stock fresh at its current $35 price — there is no rational reason to hold it simply because you once paid $50 for it. The $15 loss is already gone. Refusing to sell doesn't recover it; it just delays the recognition while the position may deteriorate further.

This is a direct manifestation of sunk cost reasoning: allowing past, unrecoverable costs to influence present decisions. The investor who holds a losing stock "waiting to get even" is paying an ongoing opportunity cost — the alternative uses of the capital tied up in the position — to avoid the psychological discomfort of realising a loss.

The Tax Dimension

The disposition effect is not only psychologically costly — in most tax jurisdictions, it is also fiscally irrational. In systems where capital gains are taxed upon realisation, rational tax management suggests the opposite of the disposition effect: you should consider realising losses (to offset gains and reduce tax) and deferring gains (to delay the tax liability). This strategy — tax-loss harvesting — involves selling losing positions before year-end to generate taxable losses that reduce your overall tax bill.

Investors subject to the disposition effect do the reverse: they sell winners (triggering immediate capital gains tax) and hold losers (forgoing the tax benefit of realising the loss). The result is a double penalty — worse pre-tax performance, and worse post-tax performance. A rational investor who considered only tax efficiency would exhibit the exact opposite of the disposition effect.

This disconnect between the behaviour we observe and the behaviour that tax logic recommends makes the disposition effect particularly compelling evidence that the psychology of loss aversion, not rational calculation, is driving decisions.

Professional Investors Are Not Immune

It is tempting to assume that professional fund managers — trained, incentivised, and monitored — would be free of this bias. The evidence is mixed at best. Studies of mutual fund managers by Frazzini (2006) found clear evidence of the disposition effect in professional portfolios: managers held losers and sold winners at rates inconsistent with rational portfolio management, and this behaviour was associated with worse fund performance.

Some evidence suggests that experienced traders on short-term horizons (intraday futures traders, for example) exhibit weaker disposition effects — the feedback loops are faster and the incentives to cut losses are clearer. But in longer time-horizon investing, where the pain of a loss can be deferred almost indefinitely, the effect persists even among professionals.

Practical Countermeasures

The disposition effect is well-understood and yet stubborn. Several strategies reduce its grip:

• Pre-commit to rules. Systematic rules — "I will sell any position that falls more than 15% below purchase price" (a stop-loss rule) or "I will rebalance my portfolio to target weights annually" — remove individual hold/sell decisions from the realm of emotional judgment. Rules bypass the moment-of-decision pain of realising a loss.
• Reframe the question. Instead of "should I sell this losing position?", ask: "Would I buy this asset at its current price, today, with no prior history?" This removes the purchase price from the decision and forces an honest forward-looking assessment.
• Tax-loss harvest deliberately. Making tax-loss harvesting an active practice turns the disposition effect on its head. You are now looking for losses to realise — which counteracts the psychological reluctance to sell below purchase price.
• Separate "paper" from "real" losses. Recognise that an unrealised loss is economically equivalent to a realised one — the wealth is equally gone. The distinction between "on paper" and "real" exists only psychologically, not financially.

The disposition effect is a reminder that markets are not populated by emotionless rational actors but by humans carrying reference points, loss aversion, and the deep need to avoid admitting a mistake. Understanding this — in yourself and in markets — is one of the more durable edges in long-term investing.

Sources & Further Reading

• Shefrin, H., & Statman, M. "The Disposition to Sell Winners Too Early and Ride Losers Too Long: Theory and Evidence." Journal of Finance 40, no. 3 (1985): 777–790.
• Kahneman, D., & Tversky, A. "Prospect Theory: An Analysis of Decision Under Risk." Econometrica 47, no. 2 (1979): 263–291.
• Odean, T. "Are Investors Reluctant to Realize Their Losses?" Journal of Finance 53, no. 5 (1998): 1775–1798.
• Frazzini, A. "The Disposition Effect and Under-Reaction to News." Journal of Finance 61, no. 4 (2006): 2017–2046.
• Wikipedia: Disposition effect