The Sunk Cost Fallacy:Why You Keep Holding an Investment That Isn't Working

You've held a position for two years. It hasn't performed the way you expected. Every honest evaluation of the current facts suggests it no longer fits your plan. And yet, selling feels wrong — not because of what the position might do next, but because of everything you've already put into it: the money, the research, the waiting. That feeling has a name: the sunk cost fallacy.

What is the sunk cost fallacy?

The sunk cost fallacy is the tendency to continue a decision based on the resources already invested in it — time, money, effort — rather than on a clear-eyed evaluation of its future prospects. In investing, this typically shows up as holding onto a losing position specifically because of how much has already been put in, even when the case for holding, evaluated fresh, wouldn't stand on its own.

The core error is treating past costs as relevant to a future decision. Rationally, money already spent is gone regardless of what you do next. The only question that should matter is: given where things stand today, is this still a good use of your capital going forward? The sunk cost fallacy quietly replaces that question with a different one: "how do I justify what I've already spent?"

How it connects to anchoring and loss aversion

The sunk cost fallacy rarely operates alone. It's closely tied to anchoring bias, where your original purchase price becomes a fixed reference point, and to loss aversion, where the pain of realizing a loss feels sharper than the relief of avoiding further decline. Together, these forces create a powerful pull toward holding: selling would mean admitting the original decision hasn't worked out, and that admission — not the financial outcome itself — is often what people are unconsciously trying to avoid. This pull tends to be strongest for investors with a protective, loss-sensitive pattern like the Fear Defender archetype.

How the sunk cost fallacy shows up in real decisions

• "I've come this far" reasoning: continuing to hold, or even adding to, a position specifically because of how long you've already held it, rather than because the current case is strong.
• Doubling down to recover losses: increasing a position specifically to lower your average cost and "get back to even" faster, rather than because the additional investment is independently justified.
• Avoiding review altogether: unconsciously avoiding a clear-eyed look at a struggling position because some part of you doesn't want to confront the evidence that it isn't working.
• Emotional attachment to the research: feeling that abandoning a position would waste not just money but also the hours spent researching and understanding it, as if walking away erases that effort.

A hypothetical example

Imagine Taylor invested in a sector-focused position two years ago after significant research. The sector has since underperformed relative to Taylors original thesis, and the specific reasons Taylor bought in no longer hold up as clearly as they once did. Taylor knows this, intellectually. But every time Taylor considers selling, the thought arrives: "I've already been through two years of ups and downs with this position — if I sell now, all of that was for nothing." Taylor holds on, not because the forward-looking case is compelling, but because exiting would mean acknowledging that two years of patience didn't pay off the way it was supposed to. The two years spent are gone either way; the only real question left is what to do from here.

How to evaluate positions without the sunk cost trap

1) Ask the fresh-capital question

The clearest antidote: "If I had this money in cash today, with no prior history with this position, would I choose to buy it right now?" If the answer is no, the time and money already invested aren't a good reason to keep holding.

2) Separate effort from evidence

The amount of research or attention you've put into a position says nothing about whether it's still a good holding today. Effort is not evidence. Write down what the current, forward-looking case actually is, independent of how much work went into the original decision.

3) Reframe "selling" as reallocating, not failing

Exiting a position that no longer fits isn't an admission that the original decision was foolish — it's simply updating a decision based on new information, which is a normal and healthy part of long-term investing, not a personal failure.

4) Set a pre-defined review trigger

Decide in advance what conditions would prompt a genuine re-evaluation of a position — not a price target, but a change in the underlying thesis. This gives you a structured way to revisit a decision without needing to first overcome the emotional resistance of "giving up" on it, similar in spirit to the discipline behind dollar-cost averaging.

FAQ

Is the sunk cost fallacy the same as loss aversion?

They're related but different. Loss aversion is the general tendency to feel losses more intensely than equivalent gains. The sunk cost fallacy is more specific: it's the tendency to let past investment of time or money influence a decision about the future, even though that past investment is unrecoverable either way.

Isn't it reasonable to give an investment more time before giving up?

Genuine patience based on an intact, well-reasoned thesis is different from the sunk cost fallacy. The distinguishing question is whether you'd still choose to hold based on the current evidence alone, or whether the primary reason is what you've already put in.

How do I know if I'm falling into this pattern?

A common sign is discomfort or avoidance when you try to evaluate a position freshly, as if you'd never owned it. If that exercise feels harder than it should, the sunk cost fallacy may be influencing your thinking.

Does the sunk cost fallacy only apply to losing positions?

It most commonly shows up with underperforming positions, but the same pattern can affect any decision where past effort or cost influences a forward-looking choice, including non-financial decisions.

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Disclaimer

This article is for educational and informational purposes only and does not provide financial advice, investment recommendations, or predictions.