A corporation has the option to prepay (call) a bond with 4 years to maturity, $50M in remaining principal, a 10% yearly rate, fixed and YEARLY payments. It can replace this bond with a 4 year bond with the same remaining payment structure. Prepayment penalties are $750,000. The corporation faces a tax rate of 30% on its EBIT. How low must the yearly rate on the new bond be to justify calling the old bond (ignoring the option value of waiting to refi but taking into account the loss in interest tax shield)?