When is a sunk cost relevant in DCF analysis?

In discounted cash flow (DCF) analysis, sunk costs are typically deemed irrelevant because they represent expenses that have already been incurred and cannot be recovered, regardless of future outcomes. Since DCF focuses on the analysis of future cash flows and the incremental costs and benefits associated directly with a decision, sunk costs do not influence those future evaluations.

For instance, if a company has spent money on a project that has not gone as planned, that previous investment should not factor into the decision of whether to continue investing in the project or pivot to a new opportunity. Decisions should be based solely on future cash flows expected from each alternative, rather than on past expenditures. Thus, recognizing the irrelevance of sunk costs is essential in making objective investment decisions that are based on forward-looking projections.