Answer:
6.66%
Explanation:
First and foremost, if a bond is issued at par it means that the coupon rate and before-tax yield to maturity are the same. hence, in this case, the before-tax yield on the bond is 8.10%, the same as its coupon rate
after-tax yield on bond=before-tax yield*(1-tax rate)
tax rate=40%
the after-tax yield on bond=8.10%*(1-40%)
the after-tax yield on bond=4.86%
after-tax return on the preferred=the after-tax yield on bond+after-tax risk premium
after-tax risk premium=1.0%
after-tax return on the preferred=4.86%+1.0%
after-tax return on the preferred=5.86%
However, the before-tax coupon rate on the preferred is determined below based on the dividend received deduction principle obtainable in the US
Pre-Tax Coupon Rate = after-tax return on the preferred/(1-(Tax Rate*Taxable Percentage)
The principle that 70% of dividends, that only 30% are taxable, hence, the taxable percentage is 30%
Pre-Tax Coupon Rate =5.86%/(1-(40%*30%)
Pre-Tax Coupon Rate =5.86%/0.88
Pre-Tax Coupon Rate =6.66%