Greed in Trading: How to Keep a Winning Day a Winning Day

What is greed in trading?

Greed in trading is letting a good run push you past your plan. At the desk it rarely feels like greed. It feels like confidence: the setups are working, you are reading the market well, and it seems a waste not to press.

The damage comes later in the day or the week. Size goes up, targets move and trading continues after the goal was reached, until the gains are gone. Fear is the other half of the same swing, covered in fear and greed in trading.

What are the signs greed is driving your trades?

One or two of these on a single day is normal. The same sign on most winning days is a pattern worth a rule.

What is the house money effect?

The house money effect is the tendency to take more risk after a gain, as if money you just won is not really yours yet. Thaler and Johnson named it in 1990 after real-money experiments in which a prior gain made people more willing to take the next gamble. They also found the mirror image, the break-even effect: after a loss, a chance to get back to even becomes especially attractive.

It shows up in real markets too. Liu, Tsai, Wang and Zhu (2010) studied Taiwan's index options market and found a strong link between earlier results and later risk: after morning gains, traders took above-average risk in the afternoon. The pattern appeared in the accounts of professional market makers as well as other participants.

For a day trader it looks like this: a green morning, then bigger size or looser entries in the afternoon, because the day "is already paid for". It is not. The afternoon trades are paid for from the same account as the morning ones. The loss side of the curve, where traders take more risk to get back to even, is covered under loss aversion.

What is overconfidence bias in trading?

Overconfidence bias is rating your skill or information higher than your results support. In trading, it shows up as trading too often and too big, and as putting wins down to skill and losses down to bad luck.

The evidence is strongest for trading volume:

• The households that traded most earned the least. Barber and Odean (2000) studied 66,465 households at a large US discount broker from 1991 to 1996. Those that traded most earned 11.4% a year while the market returned 17.9%. The authors argued overconfidence can explain the heavy trading.
• The more overconfident group traded more. In a second study of over 35,000 households, Barber and Odean (2001) used gender as a stand-in, because psychology research finds men more overconfident than women in areas such as finance. Men traded 45% more than women, and trading cut their net returns by 2.65 percentage points a year, against 1.72 for women.
• Wins can teach overconfidence. Gervais and Odean (2001) built a model in which traders take too much credit for their successes and become overconfident, most of all early in their careers. It is a theory, not a measurement, but it describes the trader who sizes up after a hot week.
• Euphoria is not harmless. Lo, Repin and Steenbarger (2005) followed 80 day traders for five weeks. Those whose emotional reactions to gains and to losses were more intense performed worse. The finding is a correlation, not proof of cause.

The first three studies looked at stock investors or at a model, not at day traders. They show a direction, not a number for you.

How do I control greed in trading?

Five rules, all set before the session, when nothing is at stake:

1. A fixed size rule. Decide your risk per trade, for example in R, before the open, and keep it the same all session whatever your P&L. If you want to change it, change the written plan outside market hours, based on a large sample of trades, not one good morning. This is not a size recommendation; the right rule is one you will keep.
2. A green-day rule. Decide in advance what ends a winning day. The next section has three versions.
3. A scale-out plan. If you take partial profits, decide where and how much before entry. Exits decided mid-trade are where greed moves targets and fear cuts winners, the disposition effect.
4. No new risk after your target. Once you reach your daily goal, you manage open trades by your plan and open no new ones. As an if-then rule: "If I reach my daily target, then I close the platform once my open trades are done."
5. An end-of-day review. Three questions: did I keep my size rule, did I keep my green-day rule, and how much of today was luck? Write the answers down, especially on your best days.

For more rules in the same format, see trading discipline rules.

When should I stop trading on a green day?

There is no agreed rule, and no study sets a number. What matters is that you choose one before the open, when a winning day is still hypothetical.

You can combine two, for example a target and a trade cap. The trade cap matters most on winning days, because overtrading after wins is how a green morning turns into a red afternoon. On losing days, a daily loss limit does the same job.

Is greed the same as ambition?

No. Ambition sets goals in advance and works on the process that reaches them. Greed changes the goal in the middle of the session because the day is going well.

A simple test: if the size, target and rules you are using now are the ones you wrote before the open, that is ambition. If you changed them after a win, that is greed. The trading psychology guide shows where this fits among the other patterns that break a plan.

How does TradeMind help with greed?

Everything above works with a pen and a journal. TradeMind: Trading Psychology, the iPhone trading psychology app (App Store ID 6761249038) by Nikolaos Aristotelis Adamidis, adds lessons and routines built for the moments after a win.

• The Taming Greed track (Profit Management). Ten audio lessons of about 3 to 6 minutes each: The Euphoria Trap, Overconfidence Bias, The Disposition Effect, Position Sizing Math, Scaling Out, The Moving Goalpost, Giveback Prevention, Visualizing Reversal, Compounding Logic and Enough is Enough. Each has written notes and 2 journal prompts. The Moving Goalpost adds a pre-mortem: picture a day on which you were up, kept trading for a little more and finished red. Enough is Enough asks you to define your own "enough" number. See the Taming Greed track.
• Victory Grounding. One of four guided resets, subtitled "Maintain humility." in the app. It runs three timed steps: a one-minute centering, two minutes of paced breathing (4 seconds in, 6 out), and a three-minute visualisation in which a trade goes against you and you accept the loss. It may help you slow down after a win. It does not change the odds of your next trade.
• End of Day Review. Another reset, whose last step, Luck Attribution, asks how much of the day's result was luck.
• The TradeMind Daily Pledge. Before the open you set a daily loss limit, a maximum number of trades (1 to 12) and one if-then guardrail, sealed with a 1.5-second hold. One trigger is "I'm on a winning streak", with responses such as "step away for 10 minutes" or "close the platform for the day". If you told the app's quiz that your worst decisions come after a winning streak, the pledge pre-selects that trigger. It is self-reported: TradeMind does not connect to your broker.
• The saboteur quiz. In the free 8-question quiz, one answer to "When your discipline breaks, what takes the wheel?" is over-leveraging for the rush. Choose it and your result names you a Leverage Chaser and starts you on The Euphoria Trap. In The Ascent, the app's six-chapter progress path, the chapter called The Slayer then asks you to finish the Taming Greed track.
• Points for the process. Discipline Points come from the pledge, lessons, journaling and resets. The app states it plainly: "Points reward the process, never your P&L." A green day earns nothing extra, and a red day on which you kept your rules loses nothing.