Maria's car dealership is currently all equity financed, and has a cost of equity of 10.4%. After some consideration, she decided that she could significantly cut her tax bill without risking financial distress if 39% of her firm was financed with perepetual debt. She can borrow at 4.9%, and her tax rate is 23%. What will Maria's cost of equity be according to Modigliani-Miller? Please enter your answer as a decimal to at least three places - 8.6% should be 0.086, for example.