If your firm issues a 10-year semiannual payment bond and you are trying to calculate the associated after-tax cost of debt, you would have to calculate the

• Acapital gains yield, which you would convert to an effective yield and then multiply the result by (1 minus the average tax rate).
• B capital gains yield, which you would convert to an semiannual rate and then multiply the result by (1 minus the marginal tax rate).
• Cpromised yield to maturity, which you would convert to an effective yield and then multiply the result by (1 minus the average tax rate).
• Dpromised yield to maturity, which you would convert to an effective yield and then multiply the result by (1 minus the marginal tax rate).