The Refunding of Discounted Debt: An Adjusted Present Value Analysis
运用调整现值法分析折价债务再融资，指出新债利率高于旧债时，利息税盾增加可能带来收益，但数值模拟表明再融资通常不盈利。
In a recent article [5], Gene Laber discusses two models for the analysis of bond refunding. The Adjusted Discount Rate method handles tax benefits of new debt financing by using an after-tax rate to discount the incremental cash flows of a proposed refunding. The Adjusted Present Value method (building on work by Myers [8]) uses pre-tax discount rates but adds the tax shields of new debt to the cash flows. Laber demonstrates that the two models can yield conflicting answers. He recommends the Adjusted Present Value method because it 1) spells out the financing assumptions made in a refunding analysis, and 2) involves essentially the same computational effort as the adjusted discount rate approach. Throughout his paper, Laber discusses the case in which the existing bond is to be replaced by a newlyissued bond carrying a lower coupon rate. The purpose of this note is to apply Laber's framework to the refunding of discounted debt in which the newly-issued bond carries a coupon rate higher than that of the old bond. As will be demonstrated, the Adjusted Present Value method clearly displays the reasons for potential benefits in refunding such discounted debt. These benefits result from increased corporate tax shields on interest payments. That these benefits exist supports earlier work (e.g., Kalotay [4]); however, plausible numerical values still suggest that the refunding of discounted debt is not likely to be profitable (supporting, for example, Laber [6]). Specific conclusions on the desirability of such refundings must await detailed empirical research.