The required rate of return on shares of ABC Corp, with equal amounts of debt and equity, is $8\mathrm{.}5\%.$ ABC Corp manufactures electronic components for driverless cars. ABC Corp went on a borrowing spree and ended up with three times as much debt as it had equity. The borrowing increased ABC's financial risk so equity investors now demanded a $11\mathrm{.}7\%$ return on their holdings. Bond investors, however, decided to maintain their expectations of returns. ABC Corp qualifies for a special tax break, so its marginal tax rate will be zero for a long time. At what rate should ABC discount future investment opportunities in the electronic component business?