Rune Inc. is a company with 50 million shares, trading at $40/share, and $500 million in debt outstanding. The company has a beta of 1.44 and a pre-tax cost of debt of 5%. The company is planning to double its debt to capital ratio. If the marginal tax rate is 20%, the risk free rate is 3% and the equity risk premium is 5%, what would the pre-tax cost of debt need to be at the new debt ratio, for the cost of capital to be unchanged?