Answer:
The debt cost component would change by 0.35%
Step-by-step explanation:
The after tax cost of debt before the new tax rate is implemented is computed thus:
In calculating the after tax cost of debt, the rate formula in excel needs to be used first of all to compute pre-tax cost of debt
=rate(nper,pmt,-pv,fv)
nper is the number of times the bond is expected to pay coupon interest,that is 20*2=40
pmt is the semi-annual coupon payment payable by the bond i.e$1000*7%/2=$35
The pv is the price of the bond at $1000
The fv is the face of the bond at $1000 as well
=rate(40,35,-1000,1000)
rate=3.5%
The 3.5 % is a semi-annual rate ,annual rate is 7%(3.5%*2)
After tax cost of debt at 40% tax rate =7%*(1-0.4)
=4.2%
After tax cost of debt at 45% tax rate =7%*(1-0.45)
=3.85%
The difference is 4.2%-3.85%=0.35%