Why Investors Keep Pouring Money Into Failing Projects.
The sunk cost fallacy is one of the most consistently documented decision making errors in behavioural economics, and it is directly responsible for a specific pattern this page has seen repeat across multiple stalled construction stories.
Moma Marick
9/18/20264 min read
There is a decision making trap that behavioural economists have documented with remarkable consistency across every context in which it has been studied, from financial markets to personal relationships to, with particular frequency, real estate and construction projects.
It is called the sunk cost fallacy, and its mechanism is straightforward to describe even though it is genuinely difficult to overcome once it has taken hold. A sunk cost is money, time, or effort that has already been spent and cannot be recovered, regardless of what decision is made going forward. Economic theory is unambiguous on how a sunk cost should factor into a forward looking decision. It should not factor in at all. The only question that should determine whether to continue an investment is whether continuing represents the best use of resources from this point forward, evaluated exactly as it would be if no prior investment had ever been made.
Human decision making, however, does not naturally follow this logic. Research across decades has documented that people consistently allow the size of a sunk cost to influence their willingness to continue an investment, even when they can articulate, when asked directly, that the past spending is irrelevant to the forward looking decision. The larger the sunk cost, the stronger this pull tends to be, which produces a specific and dangerous pattern. The investor who has already spent the most on a failing project is often the one most likely to continue spending, precisely because the amount already lost feels too significant to abandon.
This page has documented this exact pattern across several of the cautionary stories it has told. Franck, whose contractor claimed sixty percent completion when independent assessment revealed the true figure was fifteen percent, had already released four of six agreed payments before seeking outside help. Emmanuel, whose project sat partially built for years before he sought professional intervention, described the period before he acted as one where the difficulty of walking away from what he had already invested made stopping feel like a worse option than continuing, even as continuing under the same conditions was clearly producing worse outcomes with each additional payment.
Neither of these investors was making an irrational decision by the standards of ordinary human psychology. They were experiencing precisely the cognitive pattern the sunk cost fallacy describes, treating money already spent as a reason to keep spending, rather than treating it as irrelevant history that should have no bearing on what happens next.
The psychological mechanism behind this pattern is closely related to the loss aversion this page examined in an earlier carousel. Abandoning a project after significant investment requires explicitly acknowledging that the money already spent produced no return, a moment of concrete, undeniable loss that the investor's mind resists in a way that continuing to spend, however irrationally, does not immediately trigger. Continuing feels like maintaining the possibility that the investment will still work out. Stopping feels like converting a possible future loss into a certain, final one. This asymmetry, even though it is not economically rational, exerts real and measurable pressure on real decisions.
Breaking free of this trap requires a specific discipline, and it begins with reframing the question an investor asks themselves when evaluating whether to continue a struggling project.
The wrong question, the one the sunk cost fallacy naturally leads an investor toward, is some version of how much have I already spent on this, and can I really walk away from that much money. This question keeps the investor's attention fixed on the past, on a number that cannot be changed no matter what decision is made today.
The right question, the one that actually determines whether continuing makes sense, is entirely forward looking. Starting from today, with a clear and honest understanding of the project's actual current state, is continuing to invest in this specific project genuinely the best use of the next unit of capital available, when compared honestly against every other option, including stopping entirely.
This reframing requires comparing the stalled project against real alternatives, rather than against its own history. A project that would require an additional twenty million francs to complete, and that would then be worth thirty million francs once finished, may still be the right decision to continue, not because of what has already been spent, but because the forward looking math, twenty million invested to create thirty million in value, makes sense on its own terms. The same project, if an honest assessment revealed it would require fifty million francs to complete and would only be worth thirty million francs once finished, would not become a better decision simply because forty million francs had already been spent on it. The forward looking math would remain the same regardless of the sunk cost, because sunk costs, correctly understood, do not belong in that calculation at all.
The practical difficulty, and the reason this page consistently emphasises independent, professional assessment across every category of investment protection it has examined, is that an investor emotionally and financially invested in a project's history is rarely well positioned to conduct this forward looking evaluation objectively on their own. The same psychological pressure that makes the sunk cost fallacy powerful also makes self assessment unreliable, because the investor evaluating their own project is simultaneously the person most affected by the discomfort of concluding that continuing no longer makes sense.
This is precisely the function an independent, objective assessment serves, the kind this page has described in detail across its examination of stalled and mismanaged projects that were eventually recovered. An assessment conducted by a party with no emotional or financial stake in the project's history, evaluating only its current physical state, the realistic cost of completion, and the property's genuine value once finished, replaces the distorting influence of sunk cost with an honest, forward looking picture that the investor can then use to make the decision the fallacy would otherwise obscure.
Sunk cost feels, in the moment, like loyalty. Loyalty to a decision already made, to money already committed, to a version of the future the investor originally imagined when the project began. It is not loyalty. It is simply history, and history, however significant, cannot be changed by any decision made today.
The only decision that matters is the one that asks, honestly and independently, what makes the most sense from this point forward, evaluated on its own terms, regardless of what has already been spent to arrive here.