PurposeWhile an operation's unlevered value is objective, the value of the debt tax shield is subjective since it depends on the capital structure policy of the firm that owns the operation. The purpose of this paper is to explore the implications of this subjective nature of debt tax shield value for corporate investment decisions.Design/methodology/approachThe study develops a simple theoretical model.FindingsThe paper shows that even a low probability of selling a project in the future to a firm with a different tax shield value can significantly affect a project's weighted average cost of capital (WACC) and total value.Practical implicationsManagers should be aware of this issue when making corporate investment decisions.Originality/valueThis is the first study to address the implication of the subjective nature of debt tax shield value.