The sunk cost fallacy is the tendency to continue investing in something because you’ve already invested in it, not because it makes rational sense to do so. In trading, it means holding a losing position because you’ve already lost money on it, hoping to recover the loss instead of cutting and moving forward.
The Psychology of Sunk Costs
Your brain treats realized and unrealized losses differently. An unrealized loss (-$500 on an open trade) feels temporary. It might bounce back tomorrow. But a realized loss (-$500 from exiting) feels final. Your ego resists finality.
This is why traders hold losers and add to them, even when logic screams to exit. The money is already gone. But your brain hasn’t accepted it yet. The fallacy is thinking that accepting the loss will somehow hurt more than watching the position get worse.
Real-World Example: The Revenge Trade Spiral
A prop trader at FTMO starts with a $10,000 account. Here’s how sunk cost fallacy plays out:
Trade 1: Short GBP/USD at 1.2750, stop at 1.2800 (+50 pips risk). Trade hits stop. Loss: -$50. Exit executed cleanly.
Trade 2: Long EUR/USD at 1.0900, stop at 1.0850 (+50 pips risk). Trade drops to 1.0870 (-30 pips unrealized). Instead of exiting at plan, trader thinks: “I can’t exit now, I’m -$30. Just one more candle.” Trade drops to 1.0850. Now it hits hard stop: -$50 loss.
Sunk Cost Trap: Trader is now -$100 total. Frustrated, they take a third trade without waiting. Why? Because they have -$100 sitting in their head that feels recoverable. They risk 100 pips on a weak setup (instead of their usual 50) to make back the $50 loss. The trade fails immediately: -$100.
Total damage: -$200 in three trades.
If the trader had exited Trade 2 at -$30 as their original plan allowed, they’d be -$80 instead of -$200. The extra $120 loss came from sunk cost fallacy, not bad luck.
Why It Feels Logical at the Time
When you’re sitting in a losing trade, your brain offers this argument:
“I’m down $500 already. If I exit now, I lock it in. But if I hold, maybe tomorrow it bounces back. What if I exit and then it goes my way 10 pips later? I’ll have wasted a loss.”
This sounds rational. But it’s backward thinking. Here’s why:
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Past losses don’t predict future price movement. The market didn’t move because you lost money. Your stop hit because your setup failed or you got unlucky. Holding won’t change that.
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You’re chasing a breakeven that may never come. Even if the trade bounces, why wait for breakeven when you could be trading the next opportunity? The opportunity cost is invisible but real.
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You’re increasing risk for the same potential reward. You’ve already lost 100 pips. Holding adds 50 more pips of risk. You’re risking more to get back to even. That’s the definition of bad math.
Sunk Cost Fallacy vs. Conviction
Real conviction in a trade looks different:
| Sunk Cost Fallacy | Real Conviction |
|---|---|
| ”I’m down so much, I have to hold" | "My setup is still valid even though I’m negative” |
| Moves stop further away as trade goes against you | Stop was placed based on setup, not updated on emotion |
| Scales in to “average down” the loss | Exits if the setup no longer holds |
| Holds for breakeven, ignores new information | Updates thesis based on new price action |
| Feels like recovery | Feels like calculated risk |
A trader with real conviction in a setup might hold through drawdown if the setup is intact. But they knew they were holding when they entered. They didn’t decide to hold only after the loss happened. That’s the key difference.
How to Identify It in Your Journal
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Track “exited at plan” vs “exited off plan.” If you exit at -50 pips when your stop was at -50 pips, that’s disciplined. If you exit at -80 pips when your stop was at -50 pips, that’s sunk cost fallacy.
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Look at losing trades where you scaled in. Averaged down on a loser? That’s sunk cost fallacy. You added risk because you wanted to recover an existing loss.
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Count trades held past their stop loss. Every time you move a stop loss away from entry (giving it more room), you’re likely falling for sunk cost thinking.
Breaking the Pattern
1. Pre-decide everything before you enter. Entry, stop, target, size. Write it down. Once the trade is open, you’re not allowed to change the stop (except to tighten it). This removes emotion from the equation.
2. Treat each trade as a new decision. When a trade goes negative, ask: “If I didn’t have this trade open, would I enter it now?” If the answer is no, exit. The loss is already real. Staying in doesn’t change that.
3. Reset between trades. After exiting a loss, take a 10-minute break. Don’t immediately look for the next trade to “make it back.” This breaks the revenge trading cycle and prevents sunk cost thinking.
4. Keep a specific sunk cost journal. For every trade where you held past your stop, note how much extra loss you took. Over 50 trades, you’ll see the true cost of the fallacy.
5. Reframe losses as information. That -$50 loss told you something about the market or your execution. It cost you tuition. Now you’re educated. The money is gone regardless. You can only control what you do next.
The Hard Truth
Your sunk costs are sunk. No amount of hope will bring them back. The only variable you control is how much worse they get. Every time you hold a losing trade past your stop, you’re betting that the market will reverse specifically to benefit you. That’s not trading—that’s gambling.
PipJournal makes sunk cost thinking visible. By showing you the exact cost of holding past plan, you see the real impact of this bias. Most traders are shocked to discover that sunk cost fallacy alone costs them 1-2% of account annually.
