Quantum BiasWhy Traders Cut Winners and Hold Losers (Disposition Effect)
The oldest advice in trading, and the research that explains why it's so hard to follow.
In this article
- Where the term comes from
- The evidence from 10,000 accounts
- Professional futures traders aren't immune
- How it shows up intraday
- The math of small wins and big losses
- A quick check on your own journal
- Why the rule alone doesn't work
- Five defenses that rely on structure, not willpower
- What this means for reading research and track records
The disposition effect is the habit of selling positions that are up too fast and holding positions that are down too long. In a study of 10,000 brokerage accounts, investors took their gains about 50% more readily than their losses. Studies of professional futures traders found the same pattern, and tied it to worse results.
"Cut your losers and let your winners run" might be the most repeated line in trading. The research explains why people so often do the opposite, and why knowing the rule isn't enough.
Where the term comes from
Hersh Shefrin and Meir Statman came up with the term in The Disposition to Sell Winners Too Early and Ride Losers Too Long: Theory and Evidence, published in the Journal of Finance in 1985 (vol. 40, no. 3). They traced the behavior to four psychological forces:
- Loss aversion. A loss hurts more than an equal gain feels good, so people avoid locking one in.
- Mental accounting. Each position is treated as its own account, which people want to close at "even" if they can.
- Regret avoidance. Selling a loser means admitting a mistake.
- Self-control. Following a rule to sell losers means fighting the urge to wait.
The evidence from 10,000 accounts
Terrance Odean tested the idea with real trading records in Are Investors Reluctant to Realize Their Losses?, published in the Journal of Finance in 1998 (vol. 53, no. 5). He studied 10,000 accounts at a big U.S. discount broker from 1987 to 1993.
His method is simple enough to use on your own journal. On each day an investor sold anything, he counted:
- the gains realized, as a share of all gains available (the "proportion of gains realized", or PGR);
- the losses realized, as a share of all losses available (the "proportion of losses realized", or PLR).
Over the full year, PGR was about 14.8% and PLR about 9.8%: investors took their gains at a much higher rate than their losses. Only in December, when tax losses become useful, did the pattern flip.
Odean also found that the winners investors sold went on to beat the losers they kept. The habit cost them money, not just discipline.
Exact values from table 1 in this article. Bar lengths share a zero baseline; no new calculation or simulated price path. Read the table and its stated sample and limits in this article.
Professional futures traders aren't immune
It's tempting to see this as a beginner mistake. Research on futures trading floors says otherwise.
In Professional trader discipline and trade disposition (Journal of Financial Economics, 2005), Peter Locke and Steven Mann studied the trades of professional futures floor traders. They found that these traders, too, held losing trades longer than winning ones, and that the less disciplined traders tended to do worse.
In Do Behavioral Biases Affect Prices? (Journal of Finance, 2005), Joshua Coval and Tyler Shumway studied proprietary traders in Treasury bond futures at the Chicago Board of Trade. Traders who lost money in the morning were about 16% more likely to take above-average risk in the afternoon than traders who'd made money. Losses didn't make them more careful. They made them press.
How it shows up intraday
If you trade NQ, the disposition effect rarely means holding a stock for months. It looks more like this:
- The stop that moves. A trade goes against you, hits your stop, and you move the stop "just a little" to give it room.
- The take-profit that shrinks. A trade goes your way, and you close it at the first small profit because you "don't want to give it back".
- The afternoon revenge trade. After a losing morning, you size up to get back to even, the exact pattern Coval and Shumway measured.
- Averaging down. You add to a losing position to improve your average price, turning one decision into two.
Each one feels reasonable in the moment. Together, they give you small wins and big losses, the opposite of what most strategies need.
The math of small wins and big losses
The damage is easiest to see with round numbers. These are examples, not data from any real trader. R is the amount risked on each trade.
| Profile | Win rate | Average win (R) | Average loss (R) | Result per 10 trades (R) |
|---|---|---|---|---|
| Disciplined | 45% | 2.0 | 1.0 | 4.5 × 2.0 − 5.5 × 1.0 = +3.5 |
| Disposition-prone | 70% | 0.8 | 2.5 | 7 × 0.8 − 3 × 2.5 = −1.9 |
The second trader wins way more often and still loses money. Closing winners early lowers the average win. Moving stops raises the average loss. A high win rate is often a symptom of the disposition effect, not a sign of skill.
A quick check on your own journal
Take your last 30 trades and add two columns:
- For winners: did you get out before your planned take-profit? Yes or no.
- For losers: did you get out after your planned stop, by moving it or ignoring it? Yes or no.
If there are a lot of "yes" answers in both columns, your results are being shaped more by the disposition effect than by your setups. Fixing that is often worth more than finding a new strategy.
Why the rule alone doesn't work
Everyone has heard "cut your losers". The disposition effect sticks around because the decision gets made in the moment, under pressure, against a feeling. The rules that work against it are made ahead of time, written down and hard to change on the spot.
Five defenses that rely on structure, not willpower
1. Decide the exit before the entry. Write down the stop and the take-profit before you get in. If you can't say where you're wrong, you're not ready to trade.
2. Use bracket orders. Place the stop and the take-profit at the same time as the entry, so changing them takes an extra, deliberate step.
3. Set a daily loss limit. After a fixed loss, you're done for the day. That takes the afternoon revenge trade off the table.
4. Measure your own PGR and PLR. Once a month, run Odean's method on your journal: of the winners you could have closed, how many did you close early? Of the losers that hit your stop, how many did you extend?
5. Separate the read from the trade. A daily bias with a written invalidation tells you when the read is wrong, no matter what your position is. Once the read is invalidated, the trade has no reason to exist anymore.
What this means for reading research and track records
The disposition effect also warps track records. A journal or signal service that closes winners fast and lets losers run will show a high win rate: the win rate looks good, the account doesn't. That's why a win rate means little without the average win, the average loss and the worst loss next to it. Our guide to reading a backtest lists what to look for.
Limits
- Odean's data are stock accounts from 1987–1993, not futures day traders.
- The futures studies looked at floor traders, before electronic trading took over.
- The effect varies from person to person. Some traders show very little of it, others a lot, and your own journal is the only way to know which one you are.
Sources
- Shefrin, H., & Statman, M. (1985). The disposition to sell winners too early and ride losers too long: Theory and evidence. Journal of Finance, 40(3), 777–790.
- Odean, T. (1998). Are investors reluctant to realize their losses? Journal of Finance, 53(5), 1775–1798. Author's page
- Locke, P. R., & Mann, S. C. (2005). Professional trader discipline and trade disposition. Journal of Financial Economics, 76(2), 401–444. IDEAS/RePEc
- Coval, J. D., & Shumway, T. (2005). Do behavioral biases affect prices? Journal of Finance, 60(1), 1–34. IDEAS/RePEc
FAQ
What is the disposition effect? The habit of selling winning positions too early and holding losing positions too long.
Who discovered the disposition effect? Hersh Shefrin and Meir Statman named it in the Journal of Finance in 1985, and Terrance Odean measured it in 10,000 brokerage accounts in 1998.
Do professional traders show the disposition effect? Yes. Studies of futures floor traders found it, and found that the less disciplined traders tended to do worse.
How do I stop moving my stop loss? Enter stops as orders at the same time as the entry, and set a daily loss limit after which you stop trading.
How can I measure the disposition effect in my own trading? Compare the share of winning trades you closed early with the share of losing trades you held past your planned stop.
Is a high win rate a good sign? Not on its own. A high win rate with small average wins and big average losses is the classic fingerprint of the disposition effect. Look at the average win, the average loss and the worst loss together.
Research and education only. Not financial advice. Futures trading involves substantial risk of loss.
How this article was made: drafted with AI assistance from the research cited above; facts and figures checked by Gabriel Décarie and Karel Panneton.
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