A business owner buys a piece of equipment, spends money training the team, and invests months into making the service work. Six months later, demand is weaker than expected. Repairs are climbing. The owner insists on continuing because stopping would mean all that investment was wasted. The dilemma feels financial, but part of it is psychological.
What is a sunk cost?
A sunk cost is money, effort, or another resource already spent that cannot be recovered by choosing differently now. A past payment may explain how the company reached its current position, but it cannot by itself justify spending more. Managerial accounting treats unavoidable past costs as irrelevant when comparing future alternatives [1]. This does not mean the original decision was foolish. Information and circumstances may have changed.
Why walking away feels so difficult
Researchers Hal Arkes and Catherine Blumer described the sunk cost effect as a greater willingness to continue an undertaking after resources have already been invested [2]. The pressure can sound reasonable: “We have come too far to stop.” But that sentence says nothing about whether the next dollar or next hour is likely to produce value. A business also risks confusing persistence with sound judgment.
Ask the question from today forward
Consider this simplified hypothetical example over the next three months. A company has already spent $20,000 developing a service, and that investment cannot be recovered whether the service continues or stops. If the company continues, it expects $15,000 in additional revenue and $9,000 in additional, avoidable operating costs over those three months. The expected incremental contribution from continuing is therefore $6,000 ($15,000 minus $9,000). The $9,000 has not been deducted anywhere else in the example. If the company discontinues the service now, it must pay a $1,000 exit fee and expects no further revenue or operating costs from that service. Under these deliberately simplified assumptions, continuing is $7,000 financially better than stopping over this period: positive $6,000 versus negative $1,000. That does not establish that continuing is the best real-world choice. Additional fixed costs, taxes, the use or sale of remaining assets, alternative uses of staff and equipment, cash timing, contractual obligations, and uncertainty could change the result. The unrecoverable $20,000 does not favor either choice [1].
Three questions worth writing down
First, if we had not made the original investment, would we choose this option today? Second, what additional money, time, or obligations will each option require from this point forward? Third, what credible new evidence would cause us to reconsider? Experimental research documents the sunk-cost effect, while later theoretical work examines mechanisms that may produce this bias [2][3]. These sources explain the tendency; the three questions here are practical prompts, not a scientifically validated decision test. These questions offer a practical way to separate emotional commitment from the remaining business case.
Stopping is not always the right answer
Sometimes continuing is justified because future benefits exceed future costs or the business has credible strategic reasons to proceed. The lesson is not to abandon difficult initiatives quickly. It is to avoid using unrecoverable past spending as the deciding argument. A thoughtful owner can honor the effort already made while still making a different decision about what happens next.