(4) Return on capital increases Explanation: The interest rate is the cost of demanding or borrowing loanable funds. Alternatively, the interest rate is the rate of return from supplying or lending loanable funds. The demand for loanable funds takes account of the rate of return on capital. The rate of return on capital is the additional revenue that a firm can earn from its employment of new capital. This additional revenue is usually measured as a percentage rate per unit of time, which is why it is called the rate of return on capital.