Answer: After-tax cost of debt is 7.8%.
Step-by-step explanation:
Given that,
coupon = 10% (outstanding bonds)
yield to maturity (YTM) = 12%
marginal tax rate = 35%
The after-tax cost of debt:
After-tax cost of debt = YTM (1 - Tax rate)
= 12% (1 - 0.35)
= 0.12 (0.65)
= 0.078
= 7.8%
YTM is used in the after-tax calculation because it represents the true pre-tax cost of debt to the issuer.
Therefore, the after-tax cost of debt is 7.8%