Calculate the after-tax return of a 11.96 percent, 20-year, A-rated corporate bond for an investor in the 10% marginal tax bracket. Compare this yield to a 9.22%, 20-year, A-rated, tax-exempt municipal bond, and explain which alternative is better. Repeat the calculations and comparison for an investor in the 33 percent marginal tax bracket.

The after-tax return of a 11.96%, 20-year, A-rated coprorate bond for an investor in the 10% marginal tax bracket is __%.