Final answer:
The overall after-tax cost of the debt for the financing of the $90m project, considering the two different interest rates and the firm's marginal tax rate of 28%, is 6.36%.
Step-by-step explanation:
The overall after-tax cost of the debt for the project financed with $90 million is calculated by accounting for the interest expense on the unsecured debt and the debt from the second bank, then adjusting for the effect of the firm's marginal tax rate, which is 28%.
First, let's calculate the annual interest expense on both debts:
- Unsecured debt interest = $18m × 8% = $1.44m
- Remaining debt = $90m - $31m - $18m = $41m
- Remaining debt interest = $41m × 9.2% = $3.772m
- Total interest = $1.44m + $3.772m = $5.212m
Next, we account for the tax shield:
- Tax shield = Total interest × Tax rate = $5.212m × 28% = $1.45936m
- After-tax interest = Total interest - Tax shield = $5.212m - $1.45936m = $3.75264m
Finally, we find the percentage of the after-tax cost of debt to the total debt financed:
- Total debt = $18m + $41m = $59m
- After-tax cost of debt percentage = ($3.75264m / $59m) × 100% = 6.36%
Therefore, the correct answer is D. 6.36%.