Mullet Technologies is considering whether or not to refund a $150 million, 15% coupon, 30-year bond issue that was sold 5 years ago. It is amortizing $3 million of flotation costs on the 15% bonds over the issue's 30-year life. Mullet's investment banks have indicated that the company could sell a new 25-year issue at an interest rate of 10% in today's market. Neither they nor Mullet's management anticipate that interest rates will fall below 10% any time soon, but there is a chance that rates will increase.

A call premium of 10% would be required to retire the old bonds, and flotation costs on the new issue would amount to $6 million. Mullet's marginal federal-plus-state tax rate is 40%. The new bonds would be issued 1 month before the old bonds are called, with the proceeds being invested in short-term government securities returning 5% annually during the interim period.

1. How would I Conduct a complete bond refunding analysis. How would I calculate bond refunding's NPV?